Wir haben keine Bestätigungen.

Achtung: Bitte tragen Sie einen Kittel, Handschuhe und Schutzbrille und lesen Sie Sicherheitsdatenblätter (SDB) vor Gebrauch zu. Alle eingekauften Materialien wurden ohne weitere Reinigung verwendet.
1. Vorbereitung von Emulsionen bestehend aus Styrol/PFO/wässrige SDS-Lösung-Mischungen
<ol><li>Um 5 mM SDS Wasserlösung vorzubereiten, lösen Sie 14,5 mg des SDS in 10 mL hochreines H2O auf. Hinweis: Hochreines H2O verwendet wurde (Widerstand (R) = 18 cm MΩ, Oberflächenspannung (γ) = 72,0 Mio. m-1 bei 25 ° C).</li>
	<li>Eine 10 mL-Glasflasche mit Stir Bar 1,5 g Styrol, 0,6 g PFO und 0,9 g 5 mm wässrige SDS-Lösung hinzufügen. Hinweis: Beim Scannen konfokale Fluoreszenz-Mikroskopie-Beobachtungen, hinzugeben Sie 2,6 mg Cumarin 102 und 0,062 mg von Calcein zur Mischung.</li>
	<li>Rühren Sie die Mischung für 60 min bei 1.150 u/min bei Raumtemperatur und heben Sie dann die Temperatur auf 80 ° C.</li>
	<li>Rühren Sie die Mischung für 60 min bei 1.150 u/min und 80 ° C.</li>
</ol>2. Herstellung von Emulsionen besteht von Styrol/PFO/wässrige SDS-Lösung Mischungen Polymerpartikel
<ol><li>Eine 10 mL-Glasflasche mit Stir Bar 3,9 mg Kalium disulfat, 2 mg pyren, 1,5 g Styrol, 0,6 g PFO und 0,9 g 5 mm wässrige SDS-Lösung hinzu und versiegeln Sie es mit einem Gummiseptum.</li>
	<li>Ebenso die Mischung von sprudelnden Stickstoffgas durch eine Spritzennadel für 30 Minuten. Achtung: Langsam fließen Stickstoffgas um keine große Menge an Schaum zu erzeugen.</li>
	<li>Zur Vorbereitung der Emulsion, rühren Sie die Mischung für 60 min bei 1.150 u/min und Raumtemperatur und heben Sie dann die Temperatur auf 80 ° C.</li>
	<li>Rühren Sie die Mischung für 30 min bei 1.150 u/min und 80 ° C.</li>
	<li>Übertragen Sie die trüben Teil (1,8 mL) in die resultierende Lösung (3 mL) in das Teströhrchen und fügen Sie dann 30 % wässrige Ethanol Lösung um die Polymerisationsreaktion vollständig zu beenden.</li>
	<li>Beschallen (Leistung: 130 W, Frequenz: 4,2 kHz) für 10 min waschen resultierenden Polymerteilchen und dann für 10 min bei 2300 X g zentrifugieren.</li>
	<li>Um die Polymerpartikel zu erhalten, entfernen Sie die überstehende Lösung aus dem Reagenzglas.</li>
	<li>Die daraus resultierende Feststoffe im Reagenzglas 3 mL Wasser hinzufügen. Beschallen (Leistung: 130 W, Frequenz: 4,2 kHz) für 10 min und Zentrifuge für 10 min bei 2300 X g. die überstehende Lösung aus dem Reagenzglas zu entfernen.</li>
	<li>Wiederholen Sie Schaum entsteht nicht aus der überstehenden Lösung des Waschvorgangs (Schritt 2.8). Verdunstet Wasser um die feste der hohlen Polymerpartikel zu erhalten.</li>
</ol>3. Vorbereitung der Mikrokapseln mit der hohlen Polymerpartikel
<ol><li>Fügen Sie 1 mg hohlen Polystyrol Partikel (Schritt 2,9) und 4 mL Wasser zu einem 10 mL-Glas-Fläschchen mit Stir Bar.</li>
	<li>Beschallen (Leistung: 130 W, Frequenz: 4,2 kHz) für 10 min in die hohle Partikel im Wasser zu dispergieren.</li>
	<li>Fügen Sie 0,1 mL Toluol zum Wasser die Partikel dispergiert und rühren Sie es für 1 h bei 100 u/min bei Raumtemperatur. Übertragen Sie die Flüssigkeit in ein Reagenzglas. Achtung: Wenn die Umdrehung pro Minute erhöht, wird die Morphologie der Partikel verformen.</li>
	<li>Zentrifugieren Sie die Flüssigkeit für 10 min bei 2300 X g zu isolieren, die Mikrokapseln bilden es. Entfernen Sie die überstehende Lösung aus dem Reagenzglas.</li>
</ol>

<ol>
	<li>Okubo, M., Fujibayashi, T., Terada, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+of+micron-sized,+monodisperse+polymer+particles+of+disc-like+and+polyhedral+shapes+by+seeded+dispersion+polymerization.">Synthesis of micron-sized, monodisperse polymer particles of disc-like and polyhedral shapes by seeded dispersion polymerization.</a> Colloid Polym Sci. 283 (7), 793-798 (2005).</li><li>Fujibayashi, T., Okubo, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+and+Thermodynamic+Stability+of+Micron-Sized,+Monodisperse+Composite+Polymer+Particles+of+Disc-like+Shapes+by+Seeded+Dispersion+Polymerization.">Preparation and Thermodynamic Stability of Micron-Sized, Monodisperse Composite Polymer Particles of Disc-like Shapes by Seeded Dispersion Polymerization.</a> Langmuir. 23 (15), 7958-7962 (2007).</li><li>Okubo, M., Fujibayashi, T., Yamada, M., Minami, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Micron-sized,+monodisperse,+snowman/confetti-shaped+polymer+particles+by+seeded+dispersion+polymerization.">Micron-sized, monodisperse, snowman/confetti-shaped polymer particles by seeded dispersion polymerization.</a> Colloid Polym Sci. 283 (9), 1041-1045 (2005).</li><li>Xu, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generation+of+Monodisperse+Particles+by+Using+Microfluidics:+Control+over+Size,+Shape,+and+Composition.">Generation of Monodisperse Particles by Using Microfluidics: Control over Size, Shape, and Composition.</a> Angew Chem Int Ed. 44 (5), 724-728 (2005).</li><li>Serra, C. A., Chang, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidic-Assisted+Synthesis+of+Polymer+Particles.">Microfluidic-Assisted Synthesis of Polymer Particles.</a> Chem Eng Tech. 31 (8), 1099-1115 (2008).</li><li>Higuchi, T., Yabu, H., Shimomura, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simple+preparation+of+hemispherical+polystyrene+particles.">Simple preparation of hemispherical polystyrene particles.</a> Colloids Surf A. 284, 250-253 (2006).</li><li>Sun, Z. Q., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nonspherical+Colloidal+Crystals+Fabricated+by+the+Thermal+Pressing+of+Colloidal+Crystal+Chips.">Nonspherical Colloidal Crystals Fabricated by the Thermal Pressing of Colloidal Crystal Chips.</a> Langmuir. 21 (20), 8987-8991 (2005).</li><li>Deng, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+approach+to+the+construction+of+3-D+ordered+macrostructures+with+polyhedral+particles.">A novel approach to the construction of 3-D ordered macrostructures with polyhedral particles.</a> J Mater Chem. 18 (4), 408-415 (2008).</li><li>Hyuk Im, S., Jeong, U., Xia, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polymer+hollow+particles+with+controllable+holes+in+their+surfaces.">Polymer hollow particles with controllable holes in their surfaces.</a> Nat Mater. 4 (9), 671-675 (2005).</li><li>Saito, N., Kagari, Y., Okubo, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+Colloidal+Stabilizer+on+the+Shape+of+Polystyrene/Poly(methyl+methacrylate)+Composite+Particles+Prepared+in+Aqueous+Medium+by+the+Solvent+Evaporation+Method.">Effect of Colloidal Stabilizer on the Shape of Polystyrene/Poly(methyl methacrylate) Composite Particles Prepared in Aqueous Medium by the Solvent Evaporation Method.</a> Langmuir. 22 (22), 9397-9402 (2006).</li><li>Cai, P. -. j., Tang, Y. -. j., Wang, Y. -. t., Cao, Y. -. j. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fabrication+of+polystyrene+hollow+spheres+in+W/O/W+multiple+emulsions.">Fabrication of polystyrene hollow spheres in W/O/W multiple emulsions.</a> Mater Chem Phys. 124 (1), 10-12 (2010).</li><li>Liang, S. -. S., Chen, S. -. L., Chen, S. -. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diverse+macroporous+spheres+synthesized+by+multiple+emulsion+polymerization+for+protein+analyses.">Diverse macroporous spheres synthesized by multiple emulsion polymerization for protein analyses.</a> Chem Commun. 47 (29), 8385-8387 (2011).</li><li>Kondo, Y., Yoshino, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hybrid+fluorocarbon/hydrocarbon+surfactants.">Hybrid fluorocarbon/hydrocarbon surfactants.</a> Curr Opin Colloid Interface Sci. 10 (3-4), 88-93 (2005).</li><li>Takahashi, Y., Kondo, Y., Schmidt, J., Talmon, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Self-Assembly+of+a+Fluorocarbon-Hydrocarbon+Hybrid+Surfactant:+Dependence+of+Morphology+on+Surfactant+Concentration+and+Time.">Self-Assembly of a Fluorocarbon-Hydrocarbon Hybrid Surfactant: Dependence of Morphology on Surfactant Concentration and Time.</a> J Phys Chem B. 114 (42), 13319-13325 (2010).</li><li>Takahashi, Y., Nasu, Y., Aramaki, K., Kondo, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Unusual+viscoelastic+behavior+of+aqueous+solutions+of+fluorocarbon-hydrocarbon+hybrid+surfactant+and+its+morphological+transformations.">Unusual viscoelastic behavior of aqueous solutions of fluorocarbon-hydrocarbon hybrid surfactant and its morphological transformations.</a> J Fluor Chem. 145, 141-147 (2013).</li><li>Yoshino, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Syntheses+of+Hybrid+Anionic+Surfactants+Containing+Fluorocarbon+and+Hydrocarbon+Chains.">Syntheses of Hybrid Anionic Surfactants Containing Fluorocarbon and Hydrocarbon Chains.</a> Langmuir. 11 (2), 466-469 (1995).</li><li>Zarzar, L. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamically+reconfigurable+complex+emulsions+via+tunable+interfacial+tensions.">Dynamically reconfigurable complex emulsions via tunable interfacial tensions.</a> Nature. 518 (7540), 520-524 (2015).</li></ol>

Wir haben nichts zu veröffentlichen.

Die Emulsionen mit Janus Tröpfchen von Styrol und PFO wurden über 10 Gew.-% der Gewichtsanteil der wässrige SDS-Konzentration und jede Gewichtsanteil von Styrol und PFO erhalten. Wenn die verschiedenen Gewicht-Fraktionen der Emulsionen mit Janus Tröpfchen für 30 min polymerisiert wurde, erhalten Sie die hohlen Polystyrol-Partikel für alle Zusammensetzung. Diese Ergebnisse deuten darauf hin, dass das Protokoll demonstriert hier ist einfach. Die Polymerisationszeit in dem hier beschriebenen Verfahren können darüber hinaus den Durchmesser, Lochgröße und Loch Volumen der hohlen Polystyrol Partikel gesteuert werden.
Wir empfehlen die folgenden Mechanismus zur Herstellung von hohlen Polystyrol Partikel. Janus Öltröpfchen bestehend aus Styrol und PFO gebildet in der O/W-Emulsionen mit Mischungen von wässrigen SDS-Lösung, Styrol und PFO bei 80 ° C. PFO Tröpfchen befinden sich auf der Oberfläche von Styrol Tröpfchen. Da KPS, Initiator der Polymerisation in der Wasserphase löslich ist, wird die Polymerisation an der Schnittstelle von Styrol/wässrige SDS-Lösung vorankommen. Styrol in ternären Emulsionen wurde zu Polystyrol bei 80 ° C polymerisiert, während PFO, nachdem keine polymerisierbaren Gruppen, in Emulsionen bei dieser Temperatur blieb. Nach die Polymerisation beendet wurde, bildete sich eine Loch auf den Polystyrol Partikel durch Entfernung des PFO. Daher wurden die hohlen Schalentyp Polystyrol Partikel, ein Loch auf der Oberfläche fabrizierten Atany Gewichtsanteil von Styrol und PFO und Polymerisation jederzeit.
Zugabe einer geringen Menge von Toluol auf die hohlen Polystyrol Partikel hergestellt durch radikalische Polymerisation für 90 min bewirkt eine Abdichtung der Bohrungen auf der hohlen Polystyrol Partikel. Dieses Phänomen entspricht dem von Hyuk Et Al.9gemeldet. Selung Methode kann eine wässrige Material in die Partikel enthalten.
In diesem Artikel haben wir bewiesen, ein Herstellungsverfahren der hohlen Polymerpartikel mit Janus Öltröpfchen bestehend aus Styrol und PFO, die sich gegenseitig nicht mischbar sind. Die Art der Zubereitung von nicht-sphärische Polymerpartikel wurde bereits wegen ihrer möglichen Verwendung in verschiedenen Anwendungen untersucht. Diese Strategie mit Janus Öltröpfchen von Kohlenwasserstoff Erdöl und Fluorcarbon gelten für die Herstellung von nicht-sphärische Polymerpartikel aus verschiedenen Arten von Monomer und Drug-Delivery-System.

Während sphärische Polymerpartikel in verschiedenen industriellen Anwendungen am meisten benutzt worden sind, ist es bekannt, dass durch gesetzte Polymerisationen1,2, Grübchen Partikel, Halbkugeln, Festplatten und Ellipsoide, hergestellt worden sind 3, Foto-Polymerisation von nicht-sphärische Monomer Tröpfchen mit haarfeinen mit speziellen Geometrien4,5, Selbstorganisation mit Reprecipitation von Polymeren6und Verformung des sphärischen Polymer Partikel durch mechanische externe Kräfte7,8. Insbesondere haben hohle Polymerpartikel mit Mikrometer-Größe durch Verdampfung des ein gutes Lösungsmittel aus kugelförmigen Polymerpartikel geschwollen durch das Lösungsmittel9,10 und Polymerisation mit multiple Emulsionen hergestellt worden 11 , 12.
Dabei konzentrieren wir uns auf die Verwendung von gegenseitigen Mischbarkeit von Kohlenwasserstoff und Fluorkohlenstoff Öle bei der Herstellung der Polymerpartikel. Hybrid-Tenside haben eine Kohlenwasserstoffkette und einer Fluorcarbon-Kette im Molekül. Bisher haben wir die einzigartigen Eigenschaften des Hybrid Tenside berichtet, die nicht in herkömmliche Tenside13,14,15eingehalten werden. Wir haben auch untersucht, Emulsionen mit Kohlenwasserstoff-Öl, Fluorcarbon Öl und wässrigen Tensid-Lösung, die sich gegenseitig nicht mischbaren16sind. Allerdings gibt es nur wenige Studien der Emulsionen17. Diese Studien haben die Morphologie der Öltröpfchen bestehend aus Kohlenwasserstoff Erdöl und Fluorcarbon in wässrigen Tensid-Lösungen beschrieben.
Hier zeigen wir ein detailliertes Protokoll der Herstellung von hohlen Polymerpartikel durch radikalische Polymerisation mit Öltröpfchen in Emulsionen aus Kohlenwasserstoff-Öl, Fluorcarbon Öl und wässrigen Natrium Dodecylsulfate (SDS) Lösungen. Wir empfehlen eine neue Strategie, die sich von den herkömmlichen Methoden zur Herstellung von nicht-sphärische Polymerpartikel unterscheidet. Diese Methode kann einfach die hohlen Polymerpartikel in kurzer Zeit herzustellen. Darüber hinaus ist das Protokoll von der Vorbereitung der Mikrokapseln durch die hohlen Polymerpartikel gezeigt.

<table><tbody><tr><td>&lt;strong&gt;Material&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Sodium dodecylsulfate, 95.0%</td><td>Wako Pure Chemical Industries, Ltd.</td><td>192-08672</td><td></td></tr><tr><td>Styrene, 99.0%</td><td>Tokyo Chemical Industry Co. Ltd.</td><td>S0095</td><td></td></tr><tr><td>Perfluorooctane, 99%</td><td>Fluorochem Ltd.</td><td>8706</td><td></td></tr><tr><td>Coumarin 102, 97.0%</td><td>Tokyo Chemical Industry Co. Ltd.</td><td>C2267</td><td></td></tr><tr><td>Calcein</td><td>Dojindo Molecular Technologies, Inc.</td><td>C001</td><td></td></tr><tr><td>Potassium peroxodisulfate, 98.0%</td><td>Kanto Chemical Co., Inc.</td><td>32375-30</td><td></td></tr><tr><td>Pyrene, 97.0%</td><td>Wako Pure Chemical Industries, Ltd.</td><td>167-05302</td><td></td></tr><tr><td>Ethanol, 99.5%</td><td>Kanto Chemical Co., Inc.</td><td>14033-00</td><td></td></tr><tr><td>Toluene, 99.5%</td><td>Kanto Chemical Co., Inc.</td><td>40180-00</td><td></td></tr><tr><td>&lt;strong&gt;Name&lt;/strong&gt;</td><td>&lt;strong&gt;Company&lt;/strong&gt;</td><td>&lt;strong&gt;Catalog Number&lt;/strong&gt;</td><td>&lt;strong&gt;Comments&lt;/strong&gt;</td></tr><tr><td>&lt;strong&gt;Equipment&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Scanning Electron Microscope</td><td>Hitachi High-Technologies Corporation</td><td>S-4800</td><td></td></tr><tr><td>Scanning Transmission Electron Microscope</td><td>Hitachi High-Technologies Corporation</td><td>S-4800</td><td></td></tr><tr><td>Ultrasonic cleaner</td><td>Branson Ultrasonics, Emerson Japan, Ltd.</td><td>Model 3510</td><td></td></tr><tr><td>Centrifuge</td><td>AS ONE Corporation</td><td>CN-1050</td><td></td></tr></tbody></table>

preparation of hollow polystyrene particles and microcapsules by radical polymerization of janus droplets consisting of hydrocarbon and fluorocarbon oils

In diesem Artikel haben wir ein Verfahren zur Herstellung von hohlen Partikel und Mikrokapseln mit Öltröpfchen bestehend aus Kohlenwasserstoff Erdöl (Styrol) und Fluorcarbon gezeigt (Perfluoro -n-Oktan, PFO) in wässrigen Tensid (Natrium Dodecylsulfate, SDS) Lösungen. Da Fluorkohlenstoff Öle mit Kohlenwasserstofföle nicht mischbar sind, sind die beiden Öle getrennt. Emulsionen werden vorbereitet, indem rühren Styrol/PFO/wässrige SDS-Lösung-Mischungen bei 80 ° C. Die Art der Emulsionen und die Morphologie der Tröpfchen in die Emulsionen werden von Lichtmikroskop und Scan konfokale Fluoreszenzmikroskop beobachtet. Es wird festgestellt, dass Öltröpfchen mit Janus-Typ Morphologien bestehend aus sich gegenseitig nicht mischbaren Styrol und PFO in wässrigen Lösungen der SDS gebildet werden. Polystyrol-Partikel werden durch radikalische Polymerisation von ternären Gemischen aus Styrol/PFO/wässrige SDS-Lösung bei 80 ° c hergestellt. Die Morphologien der Polystyrol werden durch Rasterelektronenmikroskopie und scanning Transmission Electron Microscopy Beobachtungen bestätigt. Diese Beobachtungen zeigen die Vorbereitung der hohlen Polystyrol Partikel mit einem einzigen Loch an der Oberfläche. Nach unserem Kenntnisstand ist diese Methode eine neuartige Strategie mit der Mischbarkeit von Kohlenwasserstoff und Fluorcarbon Ölen. Die hohle Partikel können auch zur Vorbereitung der Mikrokapseln angewendet werden.

Licht und Scannen konfokale Fluoreszenz-Mikroskopie Beobachtungen wurden durchgeführt, um festzustellen, die Morphologie und die Zusammensetzung der Tröpfchen in die Emulsionen aus Styrol, PFO und 5 mM SDS Wasserlösung (Abbildung 1). Rasterelektronenmikroskopie (SEM) und scanning Transmission Electron Microscopy (STEM) Beobachtungen zeigten die Bildung der hohlen Teilchen und Mikrokapseln (Abbildung 2).
Die DIC und konfokalen Mikroskopie Fluoreszenzbilder von Emulsionen bestehend aus ternären Gemischen von Styrol/PFO/wässrige SDS-Lösung zeigen, dass die kontinuierliche Phase wässrige SDS-Lösung, weil grün fluoreszieren, Calcein entspricht in beobachtet wurde die kontinuierliche Phase, und daher Typ Öl-in-Wasser-Emulsionen gebildet werden (Abbildung 1a und 1 b). Diese Bilder zeigen auch, dass die Öltröpfchen bestehen aus Styrol und PFO, die sich gegenseitig nicht mischbar sind. Die DIC und konfokalen Mikroskopie Fluoreszenzbilder von Emulsionen mit Cumarin 102 zeigen, dass ein PFO Tröpfchen an der Schnittstelle zwischen Wasser und einem Styrol-Tröpfchen befindet. Die ternären Mischungen von Styrol, PFO und wässrige SDS-Lösung bei 5 mM Form Emulsionen mit Janus Öl Tröpfchen, bestehend aus Styrol und PFO.
Die SEM und Stiel Bilder der Polymerpartikel hergestellt durch radikalische Polymerisation von Styrol/PFO/5 mM wässrige SDS-Lösung-Emulsionen zeigen die Vorbereitung der hohl-sphärische Polystyrol Partikel mit einem Loch an der Oberfläche (Abb. 2a und 2 b). Die Bildungsrate, Durchmesser und Lochgröße der hohlen Polystyrol Partikel werden durch die Beobachtung 200 Partikel durch SEM und Stiel ausgewertet. Der durchschnittliche Durchmesser geschätzt von SEM Beobachtungen ist 1,3 µm. Die Größe entspricht der Durchmesser der Polymerpartikel aus dynamische Lichtstreuung Messungen geschätzt. Die Bildungsrate beträgt ca. 100 %. Die gemittelten Lochgröße und das Volumen des Lochs in der hohle Partikel sind 0,8 ± 0,4 µm und 0,9 ± 0,4 µm3, beziehungsweise. Daher wurden die hohlen Polystyrol Partikel, die eine 0,8 µm Loch durch radikalische Polymerisation von Janus Tröpfchen mit Styrol in Emulsionen hergestellt.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/56922/56922fig1.jpg"> Abbildung 1: Morphologien der Tröpfchen in Emulsionen bestehend aus Styrol, PFO und 5 mM SDS Wasserlösung. (a) Differential Interferenz-Kontrast (DIC) und (b) konfokalen Mikroskopie Fluoreszenzbilder der Emulsionen mit wässrigen fluoreszierende Calcein. (c) DIC und (d) konfokalen Mikroskopie Fluoreszenzbilder der Emulsionen enthalten öllösliche fluoreszierenden Cumarin 102. <a href="//cloudflare.jove.com/files/ftp_upload/56922/56922fig1large.jpg" target="_blank">Bitte klicken Sie hier für eine größere Version dieser Figur.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/56922/56922fig2.jpg"> Abbildung 2: Morphologien der hohlen Polystyrol Partikel und Mikrokapseln hergestellt mit Emulsionen bestehend aus Styrol, PFO und 5 mM wässrige SDS-Lösung. (a) SEM und (b) Stamm Bilder der hohlen Polystyrol Partikel. (c) SEM und (d) Stamm Bilder der Mikrokapseln. <a href="//cloudflare.jove.com/files/ftp_upload/56922/56922fig2large.jpg" target="_blank">Bitte klicken Sie hier für eine größere Version dieser Figur.</a>

Watch this Scientific Journal Video about Preparation of Hollow Polystyrene Particles and Microcapsules by Radical Polymerization of Janus Droplets Consisting of Hydrocarbon and Fluorocarbon Oils at J

Preparation of Hollow Polystyrene Particles and Microcapsules by Radical Polymerization of Janus Droplets Consisting of Hydrocarbon and Fluorocarbon Oils

Vorbereitung der hohlen Polystyrol Partikel und Mikrokapseln durch radikalische Polymerisation von Janus Tröpfchen bestehend aus Kohlenwasserstoff und Fluorcarbon-Öle

Ein Protokoll für die Herstellung von hohlen Polymerpartikel und Mikrokapseln durch radikalische Polymerisation mit Emulsionen bestehend aus Styrol, Perfluoro -n-Oktan und wässrige SDS (Natrium Dodecylsulfate) Lösung präsentiert.

In this article, we have demonstrated a method for producing hollow particles and microcapsules using oil droplets consisting of hydrocarbon oil (styrene) ...

preparation-hollow-polystyrene-particles-microcapsules-radical

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9.9K Aufrufe.  Tokyo University of Science. Ein Protokoll für die Herstellung von hohlen Polymerpartikel und Mikrokapseln durch radikalische Polymerisation mit Emulsionen bestehend aus Styrol, Perfluoro -n-Oktan und wässrige SDS (Natrium Dodecylsulfate) Lösung präsentiert.

Serie: Preparation of Hollow Polystyrene Particles and Microcapsules by Radical Polymerization of Janus Droplets Consisting of Hydrocarbon and Fluorocarbon Oils

Synthesis of Poly(N-isopropylacrylamide) Janus Microhydrogels for Anisotropic Thermo-responsiveness and Organophilic/Hydrophilic Loading Capability

Janus microparticles are compartmentalized particles with differing molecular structures and/or functionality on each of their two sides. Because of this unique property, Janus microparticles have been recognized as a new class of materials, thereby attracting a great deal of attention from various research fields. The versatility of these microparticles has been exemplified through their uses as building blocks for self-assembly, electrically responsive actuators, emulsifiers for painting and cosmetics, and carriers for drug delivery. This study introduces a detailed protocol that explicitly describes a synthetic method for designing novel Janus microhydrogels composed of a single base material, poly(N-isopropylacrylamide) (PNIPAAm). Janus microdroplets are firstly generated via a hydrodynamic focusing microfluidic device (HFMD) based on the separation of a supersaturated aqueous NIPAAm monomer solution and subsequently polymerized through exposure to UV irradiation. The resulting Janus microhydrogels were found to be entirely composed of the same base material, featured an easily identifiable compartmentalized morphology, and exhibited anisotropic thermo-responsiveness and organophilic/hydrophilic loading capability. We believe that the proposed method introduces a novel hydrogel platform with the potential for advanced synthesis of multi-functional Janus microhydrogels.

Synthesis of PolyN-isopropylacrylamide Janus Microhydrogels for Anisotropic Thermo-responsiveness and Organophilic/Hydrophilic Loading Capability

We present a protocol to synthesize Janus microhydrogels composed entirely of the same base material, poly(N-isopropylacrylamide) (PNIPAAm), with a clearly compartmentalized structure base on the phase separation of a supersaturated NIPAAm monomer solution. The synthesized Janus microhydrogels show unique properties such as anisotropic thermo-responsiveness and organophilic/hydrophilic loading capability.

Synthese von Poly (<em&gt; N</em&gt; Isopropylacrylamid) Janus Microhydrogels für anisotroper Thermo-Ansprechempfindlichkeit und organophiler / Hydrophilie Belastbarkeit

Janus microparticles are compartmentalized particles with differing molecular structures and/or functionality on each of their two sides. Because of this ...

Forschung

Chemie

Using Polystyrene-block-poly(acrylic acid)-coated Metal Nanoparticles as Monomers for Their Homo- and Co-polymerization

We present a template-free method for &#8220;polymerizing&#8221; nanoparticles into long chains without side branches. A variety of nanoparticles are encapsulated in polystyrene-block-poly(acrylic acid) (PSPAA) shells and then used as monomers for their self-assembly. Spherical PSPAA micelles upon acid treatment are known to assemble into cylindrical micelles. Exploiting this tendency, the core-shell nanoparticles are induced to aggregate, coalesce, and then transform into long chains. When more than one type of nanoparticles are used, random and block &#8220;copolymers&#8221; of nanoparticles can be obtained. Detailed procedures are reported for the PSPAA encapsulation of nanoparticles, homo- and co-polymerization of the core-shell nanoparticles, separation and purification of the resulting nanoparticle chains. Transformations of single-line chains into double- and triple-line chains are also presented. The synergy between the polymer shell and the embedded nanoparticles leads to an unusual chain-growth polymerization mode, giving long nanoparticle chains that are distinct from the products of the traditional step-growth aggregation process.

Using Polystyrene-block-polyacrylic acid-coated Metal Nanoparticles as Monomers for Their Homo- and Co-polymerization

We report protocols for &#8220;polymerizing&#8221; various types of polymer-encapsulated metal nanoparticles into long chains of &#8220;homo-&#8220; and &#8220;co-polymers&#8221;.

Verwendung Polystyrol-<em&gt; Block</em&gt; -Poly (Acrylsäure) beschichteten Metallnanopartikel als Monomere für ihre Homo- und Polymerisation

We present a template-free method for &#8220;polymerizing&#8221; nanoparticles into long chains without side branches. A variety of nanoparticles are ...

High Throughput Single-cell and Multiple-cell Micro-encapsulation

Microfluidic encapsulation methods have been previously utilized to capture cells in picoliter-scale aqueous, monodisperse drops, providing confinement from a bulk fluid environment with applications in high throughput screening, cytometry, and mass spectrometry. We describe a method to not only encapsulate single cells, but to repeatedly capture a set number of cells (here we demonstrate one- and two-cell encapsulation) to study both isolation and the interactions between cells in groups of controlled sizes. By combining drop generation techniques with cell and particle ordering, we demonstrate controlled encapsulation of cell-sized particles for efficient, continuous encapsulation. Using an aqueous particle suspension and immiscible fluorocarbon oil, we generate aqueous drops in oil with a flow focusing nozzle. The aqueous flow rate is sufficiently high to create ordering of particles which reach the nozzle at integer multiple frequencies of the drop generation frequency, encapsulating a controlled number of cells in each drop. For representative results, 9.9 &mu;m polystyrene particles are used as cell surrogates. This study shows a single-particle encapsulation efficiency Pk=1 of 83.7% and a double-particle encapsulation efficiency Pk=2 of 79.5% as compared to their respective Poisson efficiencies of 39.3% and 33.3%, respectively. The effect of consistent cell and particle concentration is demonstrated to be of major importance for efficient encapsulation, and dripping to jetting transitions are also addressed. 
Introduction 
Continuous media aqueous cell suspensions share a common fluid environment which allows cells to interact in parallel and also homogenizes the effects of specific cells in measurements from the media. High-throughput encapsulation of cells into picoliter-scale drops confines the samples to protect drops from cross-contamination, enable a measure of cellular diversity within samples, prevent dilution of reagents and expressed biomarkers, and amplify signals from bioreactor products. Drops also provide the ability to re-merge drops into larger aqueous samples or with other drops for intercellular signaling studies.1,2 The reduction in dilution implies stronger detection signals for higher accuracy measurements as well as the ability to reduce potentially costly sample and reagent volumes.3 Encapsulation of cells in drops has been utilized to improve detection of protein expression,4 antibodies,5,6 enzymes,7 and metabolic activity8 for high throughput screening, and could be used to improve high throughput cytometry.9 Additional studies present applications in bio-electrospraying of cell containing drops for mass spectrometry10 and targeted surface cell coatings.11 Some applications, however, have been limited by the lack of ability to control the number of cells encapsulated in drops. Here we present a method of ordered encapsulation12 which increases the demonstrated encapsulation efficiencies for one and two cells and may be extrapolated for encapsulation of a larger number of cells.
To achieve monodisperse drop generation, microfluidic "flow focusing" enables the creation of controllable-size drops of one fluid (an aqueous cell mixture) within another (a continuous oil phase) by using a nozzle at which the streams converge.13 For a given nozzle geometry, the drop generation frequency f and drop size can be altered by adjusting oil and aqueous flow rates Qoil and Qaq. As the flow rates increase, the flows may transition from drop generation to unstable jetting of aqueous fluid from the nozzle.14 
When the aqueous solution contains suspended particles, particles become encapsulated and isolated from one another at the nozzle. For drop generation using a randomly distributed aqueous cell suspension, the average fraction of drops Dk containing k cells is dictated by Poisson statistics, where Dk = &lambda;k exp(-&lambda;)/(k!) and &lambda; is the average number of cells per drop. The fraction of cells which end up in the "correctly" encapsulated drops is calculated using Pk = (k x Dk)/&Sigma;(k' x Dk'). The subtle difference between the two metrics is that Dk relates to the utilization of aqueous fluid and the amount of drop sorting that must be completed following encapsulation, and Pk relates to the utilization of the cell sample. As an example, one could use a dilute cell suspension (low &lambda;) to encapsulate drops where most drops containing cells would contain just one cell. While the efficiency metric Pk would be high, the majority of drops would be empty (low Dk), thus requiring a sorting mechanism to remove empty drops, also reducing throughput.15
Combining drop generation with inertial ordering provides the ability to encapsulate drops with more predictable numbers of cells per drop and higher throughputs than random encapsulation. Inertial focusing was first discovered by Segre and Silberberg16 and refers to the tendency of finite-sized particles to migrate to lateral equilibrium positions in channel flow. Inertial ordering refers to the tendency of the particles and cells to passively organize into equally spaced, staggered, constant velocity trains. Both focusing and ordering require sufficiently high flow rates (high Reynolds number) and particle sizes (high Particle Reynolds number).17,18 Here, the Reynolds number Re =uDh/&nu; and particle Reynolds number Rep =Re(a/Dh)2, where u is a characteristic flow velocity, Dh [=2wh/(w+h)] is the hydraulic diameter, &nu; is the kinematic viscosity, a is the particle diameter, w is the channel width, and h is the channel height. Empirically, the length required to achieve fully ordered trains decreases as Re and Rep increase. Note that the high Re and Rep requirements (for this study on the order of 5 and 0.5, respectively) may conflict with the need to keep aqueous flow rates low to avoid jetting at the drop generation nozzle. Additionally, high flow rates lead to higher shear stresses on cells, which are not addressed in this protocol. The previous ordered encapsulation study demonstrated that over 90% of singly encapsulated HL60 cells under similar flow conditions to those in this study maintained cell membrane integrity.12 However, the effect of the magnitude and time scales of shear stresses will need to be carefully considered when extrapolating to different cell types and flow parameters. The overlapping of the cell ordering, drop generation, and cell viability aqueous flow rate constraints provides an ideal operational regime for controlled encapsulation of single and multiple cells.
Because very few studies address inter-particle train spacing,19,20 determining the spacing is most easily done empirically and will depend on channel geometry, flow rate, particle size, and particle concentration. Nonetheless, the equal lateral spacing between trains implies that cells arrive at predictable, consistent time intervals. When drop generation occurs at the same rate at which ordered cells arrive at the nozzle, the cells become encapsulated within the drop in a controlled manner. This technique has been utilized to encapsulate single cells with throughputs on the order of 15 kHz,12 a significant improvement over previous studies reporting encapsulation rates on the order of 60-160 Hz.4,15 In the controlled encapsulation work, over 80% of drops contained one and only one cell, a significant efficiency improvement over Poisson (random) statistics, which predicts less than 40% efficiency on average.12
In previous controlled encapsulation work,12 the average number of particles per drop &lambda; was tuned to provide single-cell encapsulation. We hypothesize that through tuning of flow rates, we can efficiently encapsulate any number of cells per drop when &lambda; is equal or close to the number of desired cells per drop. While single-cell encapsulation is valuable in determining individual cell responses from stimuli, multiple-cell encapsulation provides information relating to the interaction of controlled numbers and types of cells. Here we present a protocol, representative results using polystyrene microspheres, and discussion for controlled encapsulation of multiple cells using a passive inertial ordering channel and drop generation nozzle.

Combining monodisperse drop generation with inertial ordering of cells and particles, we describe a method to encapsulate a desired number of cells or particles in a single drop at kHz rates. We demonstrate efficiencies twice exceeding those of unordered encapsulation for single- and double-particle drops.

High-Throughput-Einzel-Zell-und Multiple-Zelle Mikroverkapselung

Microfluidic encapsulation methods have been previously utilized to capture cells in picoliter-scale aqueous, monodisperse drops, providing confinement ...

Biotechnik

Facile Synthesis of Worm-like Micelles by Visible Light Mediated Dispersion Polymerization Using Photoredox Catalyst

Presented herein is a protocol for the facile synthesis of worm-like micelles by visible light mediated dispersion polymerization. This approach begins with the synthesis of a hydrophilic poly(oligo(ethylene glycol) methyl ether methacrylate) (POEGMA) homopolymer using reversible addition-fragmentation chain-transfer (RAFT) polymerization. Under mild visible light irradiation (&#955; = 460 nm, 0.7 mW/cm2), this macro-chain transfer agent (macro-CTA) in the presence of a ruthenium based photoredox catalyst, Ru(bpy)3Cl2 can be chain extended with a second monomer to form a well-defined block copolymer in a process known as Photoinduced Electron Transfer RAFT (PET-RAFT). When PET-RAFT is used to chain extend POEGMA with benzyl methacrylate (BzMA) in ethanol (EtOH), polymeric nanoparticles with different morphologies are formed in situ according to a polymerization-induced self-assembly (PISA) mechanism. Self-assembly into nanoparticles presenting POEGMA chains at the corona and poly(benzyl methacrylate) (PBzMA) chains in the core occurs in situ due to the growing insolubility of the PBzMA block in ethanol. Interestingly, the formation of highly pure worm-like micelles can be readily monitored by observing the onset of a highly viscous gel in situ due to nanoparticle entanglements occurring during the polymerization. This process thereby allows for a more reproducible synthesis of worm-like micelles simply by monitoring the solution viscosity during the course of the polymerization. In addition, the light stimulus can be intermittently applied in an ON/OFF manner demonstrating temporal control over the nanoparticle morphology.

This article describes a process for producing polymeric self-assembled nanoparticles using visible light mediated dispersion polymerization. Using low energy visible light to control the polymerization allows for the reproducible formation of self-assembled worm-like micelles at high solids content.

Einfache Synthese von wurmartigen Mizellen durch sichtbares Licht Mediated Dispersion Polymerisation mit Photoredox Katalysator

Presented herein is a protocol for the facile synthesis of worm-like micelles by visible light mediated dispersion polymerization. This approach begins ...

Anionic Polymerization of an Amphiphilic Copolymer for Preparation of Block Copolymer Micelles Stabilized by &#960;-&#960; Stacking Interactions

In this study, an amphiphilic copolymer that includes a core-forming block with phenyl groups was synthesized by living anionic polymerization of phenyl glycidyl ether (PheGE) on methoxy-polyethylene glycol (mPEG-b-PPheGE). Characterization of the copolymer revealed a narrow molecular distribution (PDI &#60; 1.03) and confirmed the degree of polymerization of mPEG122-b-(PheGE)15. The critical micelle concentration of the copolymer was evaluated using an established fluorescence method with the aggregation behavior evaluated by dynamic light scattering and transmission electronic microscopy. The potential of the copolymer for use in drug delivery applications was evaluated in a preliminary manner including in vitro biocompatibility, loading and release of the hydrophobic anti-cancer drug doxorubicin (DOX). A stable micelle formulation of DOX was prepared with drug loading levels up to 14% (wt%), drug loading efficiencies &#62; 60% (w/w) and sustained release of drug over 4 days under physiologically relevant conditions (acidic and neutral pH, presence of albumin). The high drug loading level and sustained release is attributed to stabilizing &#960;-&#960; interactions between DOX and the core-forming block of the micelles.

The key steps of living anionic polymerization of phenyl glycidyl ether (PheGE) on methoxy-polyethylene glycol (mPEG-b-PPheGE) are described. The resulting block copolymer micelles (BCMs) were loaded with doxorubicin 14% (wt%) and sustained release of drug over 4 days under physiologically relevant conditions was obtained.

Die anionische Polymerisation eines amphiphilen Copolymer zur Herstellung von Blockcopolymermicellen Stabilisiert durch π-π-Stapelwechselwirkungen

In this study, an amphiphilic copolymer that includes a core-forming block with phenyl groups was synthesized by living anionic polymerization of phenyl ...

Grafting Multiwalled Carbon Nanotubes with Polystyrene to Enable Self-Assembly and Anisotropic Patchiness

We demonstrate a straightforward protocol to graft pristine multiwalled carbon nanotubes (MWCNTs) with polystyrene (PS) chains at the sidewalls through a free-radical polymerization strategy to enable the modulation of the nanotube surface properties and produce supramolecular self-assembly of the nanostructures. First, a selective hydroxylation of the pristine nanotubes through a biphasic catalytically mediated oxidation reaction creates superficially distributed reactive sites at the sidewalls. The latter reactive sites are subsequently modified with methacrylic moieties using a silylated methacrylic precursor to create polymerizable sites. Those polymerizable groups can address further polymerization of styrene to produce a hybrid nanomaterial containing PS chains grafted to the nanotube sidewalls. The polymer-graft content, amount of silylated methacrylic moieties introduced and hydroxylation modification of the nanotubes are identified and quantified by Thermogravimetric Analysis (TGA). The presence of reactive functional groups hydroxyl and silylated methacrylate are confirmed by Fourier Transform Infrared Spectroscopy (FT-IR). Polystyrene-grafted carbon nanotube solutions in tetrahydrofuran (THF) provide wall-to-wall collinearly self-assembled nanotubes when cast samples are analyzed by transmission electron microscopy (TEM). Those self-assemblies are not obtained when suitable blanks are similarly cast from analogous solutions containing non-grafted counterparts. Therefore, this method enables the modification of the nanotube anisotropic patchiness at the sidewalls which results into spontaneous auto-organization at the nanoscale.

A procedure for the synthesis of polystyrene-grafted multiwalled carbon nanotubes using successive chemical modification steps to selectively introduce the polymer chains to the sidewalls and their self-assembly via anisotropic patchiness is presented.

Pfropfen Multiwalled Carbon Nanotubes mit Polystyrol Selbstmontage ermöglichen und anisotropen führt

We demonstrate a straightforward protocol to graft pristine multiwalled carbon nanotubes (MWCNTs) with polystyrene (PS) chains at the sidewalls through a ...

Fabrication of Polymer Microspheres for Optical Resonator and Laser Applications

This paper describes three methods of preparing fluorescent microspheres comprising &#960;-conjugated or non-conjugated polymers: vapor diffusion, interface precipitation, and mini-emulsion. In all methods, well-defined, micrometer-sized spheres are obtained from a self-assembling process in solution. The vapor diffusion method can result in spheres with the highest sphericity and surface smoothness, yet the types of the polymers able to form these spheres are limited. On the other hand, in the mini-emulsion method, microspheres can be made from various types of polymers, even from highly crystalline polymers with coplanar, &#960;-conjugated backbones. The photoluminescent (PL) properties from single isolated microspheres are unusual: the PL is confined inside the spheres, propagates at the circumference of the spheres via the total internal reflection at the polymer/air interface, and self-interferes to show sharp and periodic resonant PL lines. These resonating modes are so-called "whispering gallery modes" (WGMs). This work demonstrates how to measure WGM PL from single isolated spheres using the micro-photoluminescence (&#181;-PL) technique. In this technique, a focused laser beam irradiates a single microsphere, and the luminescence is detected by a spectrometer. A micromanipulation technique is then used to connect the microspheres one by one and to demonstrate the intersphere PL propagation and color conversion from coupled microspheres upon excitation at the perimeter of one sphere and detection of PL from the other microsphere. These techniques, &#181;-PL and micromanipulation, are useful for experiments on micro-optic application using polymer materials.

Protocols for the synthesis of microspheres from polymers, the manipulation of microspheres, and micro-photoluminescence measurements are presented.

Herstellung von Polymer-Mikrosphären für optische Resonator- und Laseranwendungen

This paper describes three methods of preparing fluorescent microspheres comprising &#960;-conjugated or non-conjugated polymers: vapor diffusion, ...

Ingenieurwesen

Microfluidic Preparation of Liquid Crystalline Elastomer Actuators

This paper focuses on the microfluidic process (and its parameters) to prepare actuating particles from liquid crystalline elastomers. The preparation usually consists in the formation of droplets containing low molar mass liquid crystals at elevated temperatures. Subsequently, these particle precursors are oriented in the flow field of the capillary and solidified by a crosslinking polymerization, which produces the final actuating particles. The optimization of the process is necessary to obtain the actuating particles and the proper variation of the process parameters (temperature and flow rate) and allows variations of size and shape (from oblate to strongly prolate morphologies) as well as the magnitude of actuation. In addition, it is possible to vary the type of actuation from elongation to contraction depending on the director profile induced to the droplets during the flow in the capillary, which again depends on the microfluidic process and its parameters. Furthermore, particles of more complex shapes, like core-shell structures or Janus particles, can be prepared by adjusting the setup. By the variation of the chemical structure and the mode of crosslinking (solidification) of the liquid crystalline elastomer, it is also possible to prepare actuating particles triggered by heat or UV-vis irradiation.

This article describes the microfluidic process and parameters to prepare actuating particles from liquid crystalline elastomers. This process allows the preparation of actuating particles and the variation of their size and shape (from oblate to strongly prolate, core-shell, and Janus morphologies) as well as the magnitude of actuation.

Mikrofluidische Vorbereitung der flüssigen kristallenen Elastomer Aktoren

This paper focuses on the microfluidic process (and its parameters) to prepare actuating particles from liquid crystalline elastomers. The preparation ...

Synthesis of Monodisperse Cylindrical Nanoparticles via Crystallization-driven Self-assembly of Biodegradable Block Copolymers

The production of monodisperse cylindrical micelles is a significant challenge in polymer chemistry. Most cylindrical constructs formed from diblock copolymers are produced by one of three techniques: thin film rehydration, solvent switching or polymerization-induced self-assembly, and produce only flexible, polydisperse cylinders. Crystallization-driven self-assembly (CDSA) is a method which can produce cylinders with these properties, by stabilizing structures of a lower curvature due to the formation of a crystalline core. However, the living polymerization techniques by which most core-forming blocks are formed are not trivial processes and the CDSA process may yield unsatisfactory results if carried out incorrectly. Here, the synthesis of cylindrical nanoparticles from simple reagents is shown. The drying and purification of reagents prior to a ring-opening polymerization of &#949;-caprolactone catalyzed by diphenyl phosphate is described. This polymer is then chain extended by methyl methacrylate (MMA) followed by N,N-dimethyl acrylamide (DMA) using reversible addition&#8722;fragmentation chain-transfer (RAFT) polymerization, affording a triblock copolymer that can undergo CDSA in ethanol. The living CDSA process is outlined, the results of which yield cylindrical nanoparticles up to 500 nm in length and a length dispersity as low as 1.05. It is anticipated that these protocols will allow others to produce cylindrical nanostructures and elevate the field of CDSA in the future.

Crystallization-driven self-assembly (CDSA) displays the unique ability to fabricate cylindrical nanostructures of narrow length distributions. The organocatalyzed ring-opening polymerization of &#949;-caprolactone and subsequent chain extensions of methyl methacrylate and N,N-dimethyl acrylamide are demonstrated. A living CDSA protocol that produces monodisperse cylinders up to 500 nm in length is outlined.

Synthese von monodispersen zylindrischen Nanopartikeln durch kristallisationsgesteuerte Selbstmontage von biologisch abbaubaren Blockcopolymeren

The production of monodisperse cylindrical micelles is a significant challenge in polymer chemistry. Most cylindrical constructs formed from diblock ...

Photochemical Initiation Of Radical Polymerization Reactions

Source: David C. Powers, Tamara M. Powers, Texas A&#38;M
In this video, we will carry out the photochemically initiated polymerization of styrene to generate polystyrene, which is an important commodity plastic. We will learn the fundamentals of photochemistry and use simple photochemistry to initiate radical polymerization reactions. Specifically, in this module we will examine the photochemistry of benzoyl peroxide and its role as a photo-initiator of styrene polymerization reactions. In the described experiments, we will investigate the role of wavelength, photon absorption, and excited state structure on the efficiency (measured as quantum yield) of photochemical reactions.

Photochemische Initiierung von radikalischen Polymerisationsreaktionen

Source: David C. Powers, Tamara M. Powers, Texas A&#38;M
In this video, we will carry out the photochemically initiated polymerization of styrene to ...

Vorbereitung der hohlen Polystyrol Partikel und Mikrokapseln durch radikalische Polymerisation von Janus Tröpfchen bestehend aus Kohlenwasserstoff und Fluorcarbon-Öle

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Synthese von Poly (

Verwendung Polystyrol-