Name: synthesis and exfoliation of discotic zirconium phosphates to obtain colloidal liquid crystals
Uploaded: 2016-05-25T13:00:00.000+00:00
Duration: 8 min 54 s
Description: Watch this Scientific Journal Video about Synthesis and Exfoliation of Discotic Zirconium Phosphates to Obtain Colloidal Liquid Crystals at JoVE.com

This work is partially supported by NSF (DMR-1006870) and NASA (NASA-NNX13AQ60G). X. Z. Wang acknowledges support from the Mary Kay O'Connor Process Safety Center (MKOPSC) at Texas A&amp;M University. We also thank Min Shuai for her guidance.

열수 방법을 사용하여 α-ZrP를 1. 합성 <ol><li> 지르 코닐 클로라이드 수화물의 6g (ZrOCl이 ·이 8H 2 O) 3.75 ㎖를 150 ㎖의 (DI) 탈 이온수에서 둥근 바닥 플라스크를 녹인다. </li><li> 격렬한 교반 (DI) 탈 이온수 8.25 ml를 추가하여 다음 단계 1.1에서 제조 된 ZrOCl 2 용액에 15 M 인산 (H 3 PO 4)를 적가의 48 ML을 추가합니다. </li><li> 80 ml의 부피의 테프론 라이닝 압력 용기에 겔상 혼합물을 수득 붓는다. 스테인레스 스틸 쉘 및 덮개, 압력 플레이트로 이루어지는 수열을 오토 클레이브에 용기를 배치하고 잘 조인다. </li><li> 24 시간 동안 200 ° C에서 대류 오븐에 열수 오토 클레이브를 놓습니다. </li><li> 반응 후, 오토 클레이브 수열 주변 냉각하에 실온에서 8 시간 동안 냉각 할 수있다. </li><li> 2에서 원심 분리기를 사용하여 냉각 후 원심 분리 관에 α-ZrP를 디스크를 수집,10 분 동안 500 XG. 상등액은 부식 반응 인산을 포함하고 있기 때문에 폐기 용기에 액체를 수집 부. <ol><li> 그 후, 다시 10 분 동안 2,500 XG에서 1 분 원심 분리기에 대한-ZrP를을 α 물 40 ml의 소용돌이를 추가합니다. 산의 모든 씻어되어 있는지 확인하기 위해이 단계를 3 번​​ 반복합니다. </li></ol></li><li> 다음 65 ° 8 시간 동안 C와의 오븐에서 건조 ZrP를 물 끈적 끈적한 혼합물 봉과 박격포를 사용하여 분쇄. </li></ol> 역류성 방법에 의한 α-ZrP를 2. 합성 <ol><li> 150 ml의 12 M 인산 산 50 ml의 둥근 바닥 플라스크에 · 8H 2 O ZrOCl 2 6g을 섞는다. </li><li> 단계 2.1에서 제조 한 혼합물을 24 시간 동안 94 ℃에서 오일 조에서 환류한다. </li><li> 단계 1.6 DI 물과 같은 프로토콜은 다음 세 번 제품을 세척 한 후 8 시간 동안 65 ° C의 오븐에서 건조시켰다. </li><li> 유봉과 박격포, 주식 F를 사용하여 분말로 건조 부피가 큰 샘플을 갈기이상 사용합니다. </li></ol> 마이크로 웨이브를 이용한 방법에 의한 α-ZrP를 3. 합성 <ol><li> 12 M 인산 용액 9 ㎖ 중에 ZrOCl 2 · 8H2O 1 g을 추가하고, 20 mL의 섬광 바이알에 잘 생성 된 혼합물을 교반한다. </li><li> 마이크로파 반응기를 위해 특정 된 10 ㎖ 유리 용기에, 상기 혼합물을 5 mL를 붓는다. </li><li> 150 ° C, 300 psi에서 압력 한계로 설정하고, 반응 온도는 반응이 1 시간 동안 일어날 수. </li><li> 반응 후, 유리 용기를 약 15 분 동안 냉각 한 후 산 세정 및 α-ZrP를 결정을 건조하는 단계 1.6-1.7에서와 동일한 절차를 수행하겠습니다. </li></ol> 단일 층으로 계층화 된 α-ZrP를 4. 각질 제거 <ol><li> 20 mL의 섬광 바이알에 DI 물 10 ㎖로 α-ZrP를 1 g의 분산. </li><li> 적어도 40 초 동안 그와 소용돌이에 TBAOH (40 중량. %)의 2.2 ML을 추가합니다. TBAOH 1로 유지된다 : ZR의 몰비 주목 한. </li><li> 1 ~ 2 시간 동안 생성 된 농축 현탁액을 초음파 처리 및 TBA + 이온과 결정의 완전한 박리의 전체 인터 할 수 있도록 3 일간 둡니다. 임의로, 농축 된 현탁액을 더 박리를 얻는 물 (2 내지 3 배 희석)로 희석 될 수있다. </li><li> 바닥에 침전 부분적으로 박리 된 결정을 제거하기 위해 1 시간 동안 높은 회전 속도 (2500 XG)에서 박리 된 샘플을 원심 분리기. 또 용기 (ZrP를 박리) 상부 수집하고, 침전은 발견되지 않을 때까지 과정을 반복한다. </li></ol>

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There is nothing to disclose.

환류 법에서는 균일 한 직경 및 두께의 α-ZrP를 소형화하기위한 좋은 선택이다. 열수 방법과 유사하게, 환류 방법이 준비 시간에 의해 제한된다. 일반적으로, 결정 성장을위한 긴 시간이 걸린다. 환류 법에 필요한 더 긴 반응 시간은보다 큰 크기 nanodisks 초래할 수있다. 박리 nanodisks의 평균 크기는 동적 광산란 (DLS)에 의해 측정된다. 본 연구에서는 박리 ZrP를 nanodisks의 크기는 19...

디스코 틱 콜로이드 점토, 아스 팔텐, 적혈구 및 진주층 형태 자연스럽게 풍부. 폴리머 나노 복합체 (1) 생체 모방 재료 기능성 멤브레인이, 디스코 틱 액정 성 시험 (3, 4)가 디스크 형 콜로이드 nanodisks에 기초하여 개발된다 피커링 에멀젼 안정제를 포함한 많은 설계 시스템의 응용의 범위. 균일 성 및 낮은 분산과 Nanodisks는 단계와 액정의 변환을 공부하는 것이 중요합니다. 지르코늄 인산 (ZrP를)는 잘 정렬 된 층 구조 및 제어 종횡비 (직경 위에 두께)와 합성 nanodisks이다. 따라서, ZrP를 다른 합성 탐사 디스코 틱 액정 시스템의 기본적인 이해를 확립 돕는다. ZrP를의 구조는 1964 년 5 클리어하고 Stynes에 의해 밝혀졌다. ZrP를 열수의 층상 결정의 합성 및환류 방법은 일반적으로 6,7을 채택하고 있습니다. 환류 방법은 동일한 지속 시간에 대한 작은 결정을 제공하는 동안 열수 방법은 400에서 25 % (6) 내에서 1,500 nm의 분산에 이르기까지 크기에 좋은 제어 할 수 있습니다. 마이크로파 가열은 나노 물질 8의 합성을위한 유망한 방법으로 입증되었습니다. 그러나, 전자 레인지를 이용한 경로에 따라 ZrP를의 합성을 설명하는 어떤 서류가 없습니다. 사이즈, 종횡비, 및 수열 법에 의한 결정 성장기구를 통해 효과적인 제어는 체계적 기 (6)에 의해 연구되었다. ZrP를 쉽게 수성 현탁액의 단일 층으로 박리 할 수 있고, 박리 ZrP를 잘 쳉의 그룹 3,9-13의 액정 재료로서 확립되었다. 지금까지, 다양한 직경 박리 ZrP를의 nanodisks는 다른 종횡비가 큰 ZrP를 낮은 콘에서 I (등방성) -N (네마 틱) 전환을 한 것으로 결론을 연구 한 말작은 ZrP를 3에 비해 자기 중심. 네마 틱 액정상의 ​​형성에 분산 3 염 (9) 및 온도 (10, 11)의 효과 또한 고려되었다. 또한, 이러한 sematic 액정 상 등의 다른 단계는도 13, 14을 조사 하였다. 이 글에서, 우리는 콜로이드 ZrP를의 nanodisks 서스펜션의 실험 실현을 보여줍니다. 계층화 ZrP를 결정은 다양한 방법을 통해 합성 한 후, 단층을 수득 nanodisks 수성 매질에서 박리된다. 끝으로,이 시스템에 의해 전시 된 액정 상 전이를 나타낸다. 이러한 디스크의 주목할만한 특징은 직경 비율 두께는 디스크 (3)의 크기에 따라 0.05 0.0007의 범위에있는 그들의 높은 이방성 특성이다. 고도의 이방성 단층 nanodisks는 nanodisks의 현탁액에 위상 전환을 연구하는 모델 시스템을 설정합니다.

<table><tbody><tr><td>&lt;strong&gt;Material&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Zirconyl Chloride Octahydrate</td><td>Fischer Scientific (Acros Organics)</td><td>AC20837-5000</td><td>98% +</td></tr><tr><td>&lt;em&gt;o&lt;/em&gt;-Phosphoric Acid</td><td>Fischer Scientific</td><td>A242-1</td><td>&amp;#8805; 85%</td></tr><tr><td>Tetra Butyl Ammonium Hydroxide</td><td>Acros Organics (Acros Organics)</td><td>AC176610025</td><td>40% wt. (1.5&amp;nbsp;M)</td></tr><tr><td>&lt;strong&gt;Equipment&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Reaction Oven</td><td>Fischer Scientific</td><td>CL2 centrifuge</td><td>Isotemperature Oven (Temperature up to 350&amp;nbsp;&amp;#176;C)</td></tr><tr><td>Centrifuge</td><td>Thermo Scientific</td><td>Not Available</td><td>Rotation Speed: 100 - 4,000 rpm</td></tr><tr><td>Microwave Reactor</td><td>CEM Corporation</td><td>Discover and Explorer SP</td><td>Temp. up to 300&amp;nbsp;&amp;#176;C, power up to 300&amp;nbsp;W, pressure up to 30&amp;nbsp;bar</td></tr></tbody></table>

synthesis and exfoliation of discotic zirconium phosphates to obtain colloidal liquid crystals

Due to their abundance in natural clay and potential applications in advanced materials, discotic nanoparticles are of interest to scientists and engineers. Growth of such anisotropic nanocrystals through a simple chemical method is a challenging task. In this study, we fabricate discotic nanodisks of zirconium phosphate [Zr(HPO4)2&#183;H2O] as a model material using hydrothermal, reflux and microwave-assisted methods. Growth of crystals is controlled by duration time, temperature, and concentration of reacting species. The novelty of the adopted methods is that discotic crystals of size ranging from hundred nanometers to few micrometers can be obtained while keeping the polydispersity well within control. The layered discotic crystals are converted to monolayers by exfoliation with tetra-(n)-butyl ammonium hydroxide [(C4H9)4NOH, TBAOH]. Exfoliated disks show isotropic and nematic liquid crystal phases. Size and polydispersity of disk suspensions is highly important in deciding their phase behavior.

그림 1A-C 쇼 각각 수열, 환류, 전자 렌지를 이용한 방법에서 얻은 α-ZrP를 nanodisks의 SEM 이미지. 그것은 α-ZrP를 nanodisks 모양과 합성 조건과 준비 방법에 따라 서로 다른 두께의 육각형 표시하는 것이 관찰되었다. 우리 그룹 6에서 이전에보고 된 연구에서 결정 성장 시간 48 시간 상기 들면 디스크의 에지가 선명해질 것을 암시한다. 통상적으로, 환류 법 수...

Watch this Scientific Journal Video about Synthesis and Exfoliation of Discotic Zirconium Phosphates to Obtain Colloidal Liquid Crystals at JoVE.com

Synthesis and Exfoliation of Discotic Zirconium Phosphates to Obtain Colloidal Liquid Crystals

A two dimensional model material of discotic zirconium phosphate was developed. The inorganic crystal with lamellar structure was synthesized by hydrothermal, reflux, and microwave-assisted methods. On exfoliation with organic molecules, layered crystals can be converted to monolayers, and nematic liquid crystal phase was formed at sufficient concentration of monolayers.

합성 및 디스코 틱 지르코늄 인산염의 각질 제거는 콜로이드 액체 크리스탈을 구하는

Due to their abundance in natural clay and potential applications in advanced materials, discotic nanoparticles are of interest to scientists and ...

synthesis-exfoliation-discotic-zirconium-phosphates-to-obtain

Universidad de Cartagena UDEC

Research

JoVE Journal

Chemistry

8.4K 조회수.  Texas A&M University. A two dimensional model material of discotic zirconium phosphate was developed. The inorganic crystal with lamellar structure was synthesized by hydrothermal, reflux, and microwave-assisted methods. On exfoliation with organic molecules, layered crystals can be converted to monolayers, and nematic liquid crystal phase was formed at sufficient concentration of monolayers. 

비디오: Synthesis and Exfoliation of Discotic Zirconium Phosphates to Obtain Colloidal Liquid Crystals

Preparation of Macroporous Epitaxial Quartz Films on Silicon by Chemical Solution Deposition

This work describes the detailed protocol for preparing piezoelectric macroporous epitaxial quartz films on silicon(100) substrates. This is a three-step process based on the preparation of a sol in a one-pot synthesis which is followed by the deposition of a gel film on Si(100) substrates by evaporation induced self-assembly using the dip-coating technique and ends with a thermal treatment of the material to induce the gel crystallization and the growth of the quartz film. The formation of a silica gel is based on the reaction of a tetraethyl orthosilicate and water, catalyzed by HCl, in ethanol. However, the solution contains two additional components that are essential for preparing mesoporous epitaxial quartz films from these silica gels dip-coated on Si. Alkaline earth ions, like Sr2+ act as glass melting agents that facilitate the crystallization of silica and in combination with cetyl trimethylammonium bromide (CTAB) amphiphilic template form a phase separation responsible of the macroporosity of the films. The good matching between the quartz and silicon cell parameters is also essential in the stabilization of quartz over other SiO2 polymorphs and is at the origin of the epitaxial growth.

A protocol is presented for the preparation of piezoelectric macroporous epitaxial films of quartz on silicon by solution chemistry using dip-coating and thermal treatments in air.

화학 용액 증착에 의해 실리콘에 거대 다공성 에피 택셜 석영 필름의 제조

This work describes the detailed protocol for preparing piezoelectric macroporous epitaxial quartz films on silicon(100) substrates. This is a three-step ...

연구

화학

Synthesis and Characterization of Supramolecular Colloids

Control over colloidal assembly is of utmost importance for the development of functional colloidal materials with tailored structural and mechanical properties for applications in photonics, drug delivery and coating technology. Here we present a new family of colloidal building blocks, coined supramolecular colloids, whose self-assembly is controlled through surface-functionalization with a benzene-1,3,5-tricarboxamide (BTA) derived supramolecular moiety. Such BTAs interact via directional, strong, yet reversible hydrogen-bonds with other identical BTAs. Herein, a protocol is presented that describes how to couple these BTAs to colloids and how to quantify the number of coupling sites, which determines the multivalency of the supramolecular colloids. Light scattering measurements show that the refractive index of the colloids is almost matched with that of the solvent, which strongly reduces the van der Waals forces between the colloids. Before photo-activation, the colloids remain well dispersed, as the BTAs are equipped with a photo-labile group that blocks the formation of hydrogen-bonds. Controlled deprotection with UV-light activates the short-range hydrogen-bonds between the BTAs, which triggers the colloidal self-assembly. The evolution from the dispersed state to the clustered state is monitored by confocal microscopy. These results are further quantified by image analysis with simple routines using ImageJ and Matlab. This merger of supramolecular chemistry and colloidal science offers a direct route towards light- and thermo-responsive colloidal assembly encoded in the surface-grafted monolayer.

A protocol for the synthesis and characterization of colloids coated with supramolecular moieties is described. These supramolecular colloids undergo self-assembly upon the activation of the hydrogen-bonds between the surface-anchored molecules by UV-light.

Control over colloidal assembly is of utmost importance for the development of functional colloidal materials with tailored structural and mechanical ...

From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding

Herein, we demonstrate that a bottom-up approach, based on halogen bonding (XB), can be successfully applied for the design of a new type of ionic liquid crystals (ILCs). Taking advantages of the high specificity of XB for haloperfluorocarbons and the ability of anions to act as XB-acceptors, we obtained supramolecular complexes based on 1-alkyl-3-methylimidazolium iodides and iodoperfluorocarbons, overcoming the well-known immiscibility between hydrocarbons (HCs) and perfluorocarbons (PFCs). The high directionality of the XB combined with the fluorophobic effect, allowed us to obtain enantiotropic liquid crystals where a rigid, non-aromatic, XB supramolecular anion acts as mesogenic core.
X-ray structure analysis of the complex between 1-ethyl-3-methylimidazolium iodide and iodoperfluorooctane showed the presence of a layered structure, which is a manifestation of the well-known tendency to segregation of perfluoroalkyl chains. This is consistent with the observation of smectic mesophases. Moreover, all the reported complexes melt below 100 &#176;C, and most are mesomorphic even at room temperature, despite that the starting materials were non-mesomorphic in nature.
The supramolecular strategy reported here provides new design principles for mesogen design allowing a totally new class of functional materials.

A protocol for the synthesis of a new type of mesogens, based on the halogen-bonded supramolecular anion [CnF2n+1-I&#183;&#183;&#183;I&#183;&#183;&#183;I-CnF2n+1]&#8722;, is reported.

분자 재료를에서: 할로겐 결합을 통해 새로운 이오니아 액체 크리스탈 엔지니어링

Herein, we demonstrate that a bottom-up approach, based on halogen bonding (XB), can be successfully applied for the design of a new type of ionic liquid ...

High Temperature Fabrication of Nanostructured Yttria-Stabilized-Zirconia (YSZ) Scaffolds by In Situ Carbon Templating Xerogels

We demonstrate a method for the high temperature fabrication of porous, nanostructured yttria-stabilized-zirconia (YSZ, 8 mol% yttria - 92 mol% zirconia) scaffolds with tunable specific surface areas up to 80 m2&#183;g-1. An aqueous solution of a zirconium salt, yttrium salt, and glucose is mixed with propylene oxide (PO) to form a gel. The gel is dried under ambient conditions to form a xerogel. The xerogel is pressed into pellets and then sintered in an argon atmosphere. During sintering, a YSZ ceramic phase forms and the organic components decompose, leaving behind amorphous carbon. The carbon formed in situ serves as a hard template, preserving a high surface area YSZ nanomorphology at sintering temperature. The carbon is subsequently removed by oxidation in air at low temperature, resulting in a porous, nanostructured YSZ scaffold. The concentration of the carbon template and the final scaffold surface area can be systematically tuned by varying the glucose concentration in the gel synthesis. The carbon template concentration was quantified using thermogravimetric analysis (TGA), the surface area and pore size distribution was determined by physical adsorption measurements, and the morphology was characterized using scanning electron microscopy (SEM). Phase purity and crystallite size was determined using X-ray diffraction (XRD). This fabrication approach provides a novel, flexible platform for realizing unprecedented scaffold surface areas and nanomorphologies for ceramic-based electrochemical energy conversion applications, e.g. solid oxide fuel cell (SOFC) electrodes.

High Temperature Fabrication of Nanostructured Yttria-Stabilized-Zirconia YSZ Scaffolds by In Situ Carbon Templating Xerogels

A protocol for fabricating porous, nanostructured yttria-stabilized-zirconia (YSZ) scaffolds at temperatures between 1,000 &#176;C and 1,400 &#176;C is presented.

에 의한 나노 구조 산화 이트륨 안정화 지르코니아 (YSZ) 비계의 고온 제작<em&gt; 시츄</em&gt; 탄소 템플릿 생성 크 세로 겔

We demonstrate a method for the high temperature fabrication of porous, nanostructured yttria-stabilized-zirconia (YSZ, 8 mol% yttria - 92 mol% zirconia) ...

공학

Orientational Transition in a Liquid Crystal Triggered by the Thermodynamic Growth of Interfacial Wetting Sheets

In liquid crystal (LC) physical chemistry, molecules near the surface play a great role in controlling bulk orientation. Thus far, mainly to achieve desired molecular orientation states in LC displays, the "static" surface property of LCs, so-called surface anchoring, has been intensively studied. As a rule of thumb, once the initial orientation of LCs is "locked" by specific surface treatments, such as rubbing or treatment with a specific alignment layer, it hardly changes with temperature. Here, we present a system exhibiting an orientational transition upon temperature variation, which conflicts with the consensus. Right on the transition, the bulk LC molecules experience the orientational rotation, with 90&#176; between the planar (P) orientation at high temperatures and the vertical (V) orientation at low temperatures in the first-order transitional manner. We have tracked thermodynamic surface anchoring behavior by means of polarizing optical microscopy (POM), dielectric spectroscopy (DS), high-resolution differential scanning calorimetry (HR-DSC), and grazing incidence X-ray diffraction (GI-XRD) and reached a plausible physical explanation: that the transition is triggered by a growth of surface wetting sheets, which impose the V orientation locally against the P orientation in the bulk. This landscape would provide a general link explaining how the equilibrium bulk orientation is affected by surface-localized orientation in many LC systems. In our characterization, POM and DS are advantageous by offering information on the spatial distribution of the orientation of LC molecules. HR-DSC gives information about the precise thermodynamic information on transitions, which cannot be addressed by conventional DSC instruments due to limited resolution. GI-XRD provides information on surface-specific molecular orientation and short-range orderings. The goal of this paper is to present a protocol for preparing a sample that exhibits the transition and to demonstrate how the thermodynamic structural variation, both in the bulk and on surfaces, can be analyzed through the abovementioned methods.

Here, we present a protocol to trigger an orientational transition of a liquid crystal in response to temperature. Methodologies are described for preparing a sample in order to observe the transition and the detailed transitional evolution.

계면 습윤지의 열역학적 성장에 의해 촉발 된 액정의 방향 전환

In liquid crystal (LC) physical chemistry, molecules near the surface play a great role in controlling bulk orientation. Thus far, mainly to achieve ...

Preparation of Liquid Crystal Networks for Macroscopic Oscillatory Motion Induced by Light

A strategy based on doped liquid crystalline networks is described to create mechanical self-sustained oscillations of plastic films under continuous light irradiation. The photo-excitation of dopants that can quickly dissipate light into heat, coupled with anisotropic thermal expansion and self-shadowing of the film, gives rise to the self-sustained deformation. The oscillations observed are influenced by the dimensions and the modulus of the film, and by the directionality and intensity of the light. The system developed offers applications in energy conversion and harvesting for soft-robotics and automated systems.
The general method described here consists of creating free-standing liquid crystalline films and characterizing the mechanical and thermal effects observed. The molecular alignment is achieved using alignment layers (rubbed polyimide), commonly used in the display manufacturing industry. To obtain actuators with large deformation, the mesogens are aligned and polymerized in a splay/bend configuration, i.e., with the director of the liquid crystals (LCs) going gradually from planar to homeotropic through the film thickness. Upon irradiation, the mechanical and thermal oscillations obtained are monitored with a high-speed camera. The results are further quantified by image analysis using an image processing program.

The goal of the protocol is to create liquid crystalline polymer films that can mechanically oscillate under continuous light irradiation. We describe in great detail the conception of free-standing films, from the liquid crystal alignment method to the photo-actuation. The experimental protocol applied to prepare this material is broadly applicable.

빛에 의해 유도 된 거시적인 진동 모션 액정 네트워크의 준비

A strategy based on doped liquid crystalline networks is described to create mechanical self-sustained oscillations of plastic films under continuous ...

Electrophoretic Crystallization of Ultrathin High-performance Metal-organic Framework Membranes

We report the synthesis of thin, highly intergrown, polycrystalline metal-organic framework (MOF) membranes on a wide range of unmodified porous and non-porous supports (polymer, ceramic, metal, carbon, and graphene). We developed a novel crystallization technique, which is termed the ENACT approach: the electrophoretic nuclei assembly for the crystallization of highly intergrown thin films (ENACT). This approach allows for a high density of heterogeneous nucleation of MOFs on a chosen substrate via the electrophoretic deposition (EPD) directly from the precursor sol. The growth of well-packed MOF nuclei leads to a highly intergrown polycrystalline MOF film. We show that this simple approach can be used for the synthesis of thin, intergrown zeolite imidazole framework (ZIF)-7 and ZIF-8 films. The resulting 500 nm-thick ZIF-8 membranes show a considerably high H2 permeance (8.3 x 10-6 mol m-2 s-1 Pa-1) and ideal gas selectivities (7.3 for H2/CO2, 15.5 for H2/N2, 16.2 for H2/CH4, and 2655 for H2/C3H8). An attractive performance for C3H6/C3H8 separation is also achieved (a C3H6 permeance of 9.9 x 10-8 mol m-2 s-1 Pa-1 and a C3H6/C3H8 ideal selectivity of 31.6 at 25 &#176;C). Overall, the ENACT process, owing to its simplicity, can be extended to synthesize intergrown thin films of a wide range of nanoporous crystalline materials.

A simple, reproducible, and versatile approach for the synthesis of intergrown, polycrystalline metal-organic framework membranes on a wide range of unmodified porous and non-porous supports is presented.

Ultrathin 높은 성능 금속-유기 프레임 워크 막의 전기 이동 화

We report the synthesis of thin, highly intergrown, polycrystalline metal-organic framework (MOF) membranes on a wide range of unmodified porous and ...

Preparation of Monodomain Liquid Crystal Elastomers and Liquid Crystal Elastomer Nanocomposites

LCEs are shape-responsive materials with fully reversible shape change and potential applications in medicine, tissue engineering, artificial muscles, and as soft robots. Here, we demonstrate the preparation of shape-responsive liquid crystal elastomers (LCEs) and LCE nanocomposites along with characterization of their shape-responsiveness, mechanical properties, and microstructure. Two types of LCEs &#8212; polysiloxane-based and epoxy-based &#8212; are synthesized, aligned, and characterized. Polysiloxane-based LCEs are prepared through two crosslinking steps, the second under an applied load, resulting in monodomain LCEs. Polysiloxane LCE nanocomposites are prepared through the addition of conductive carbon black nanoparticles, both throughout the bulk of the LCE and to the LCE surface. Epoxy-based LCEs are prepared through a reversible esterification reaction. Epoxy-based LCEs are aligned through the application of a uniaxial load at elevated (160 &#176;C) temperatures. Aligned LCEs and LCE nanocomposites are characterized with respect to reversible strain, mechanical stiffness, and liquid crystal ordering using a combination of imaging, two-dimensional X-ray diffraction measurements, differential scanning calorimetry, and dynamic mechanical analysis. LCEs and LCE nanocomposites can be stimulated with heat and/or electrical potential to controllably generate strains in cell culture media, and we demonstrate the application of LCEs as shape-responsive substrates for cell culture using a custom-made apparatus.

We demonstrate the preparation of siloxane-based and epoxy-based liquid crystal elastomers (LCEs) and LCE nanocomposites. The LCEs are characterized with respect to reversible strain, liquid crystal ordering, and stiffness. As a potential application, we demonstrate their use as shape-responsive substrates in a custom device for active cell culture.

모노 도메인 액정 탄성체 및 액정 엘라스토머 나노 복합 재료의 제조

LCEs are shape-responsive materials with fully reversible shape change and potential applications in medicine, tissue engineering, artificial muscles, and ...

생체공학

Epitaxial Nanostructured &alpha;-Quartz Films on Silicon: From the Material to New Devices

In this work, we show a detailed engineering route of the first piezoelectric nanostructured epitaxial quartz-based microcantilever. We will explain all the steps in the process starting from the material to the device fabrication. The epitaxial growth of &#945;-quartz film on SOI (100) substrate starts with the preparation of a strontium doped silica sol-gel and continues with the deposition of this gel into the SOI substrate in a thin film form using the dip-coating technique under atmospheric conditions at room temperature. Before crystallization of the gel film, nanostructuration is performed onto the film surface by nanoimprint lithography (NIL). Epitaxial film growth is reached at 1000 &#176;C, inducing a perfect crystallization of the patterned gel film. Fabrication of quartz crystal cantilever devices is a four-step process based on microfabrication techniques. The process starts with shaping the quartz surface, and then metal deposition for electrodes follows it. After removing the silicone, the cantilever is released from SOI substrate eliminating SiO2 between silicon and quartz. The device performance is analyzed by non-contact laser vibrometer (LDV) and atomic force microscopy (AFM). Among the different cantilever&#8217;s dimensions included in the fabricated chip, the nanostructured cantilever analyzed in this work exhibited a dimension of 40 &#181;m large and 100 &#181;m long and was fabricated with a 600 nm thick patterned quartz layer (nanopillar diameter and separation distance of 400 nm and 1 &#181;m, respectively) epitaxially grown on a 2 &#181;m thick Si device layer. The&#160;measured&#160;resonance frequency was&#160;267 kHz and the estimated quality factor, Q, of the whole mechanical structure was Q ~ 398 under low vacuum conditions. We observed the voltage-dependent linear displacement of cantilever with both techniques (i.e., AFM contact measurement and LDV). Therefore, proving that these devices can be activated through the indirect piezoelectric effect.

Epitaxial Nanostructured &#945;-Quartz Films on Silicon: From the Material to New Devices

This work presents a detailed protocol for the microfabrication of nanostructured &#945;-quartz cantilever on a Silicon-On-Insulator(SOI) technology substrate starting from the epitaxial growth of quartz film with the dip coating method and then nanostructuration of the thin film via nanoimprint lithography.

실리콘에 에피 택시 나노 구조α 석영 필름: 재료에서 새로운 장치에

In this work, we show a detailed engineering route of the first piezoelectric nanostructured epitaxial quartz-based microcantilever. We will explain all ...

Synthesis of Biocompatible Liquid Crystal Elastomer Foams as Cell Scaffolds for 3D Spatial Cell Cultures

Here, we present a step-by-step preparation of a 3D, biodegradable, foam-like cell scaffold. These scaffolds were prepared by cross-linking star block co-polymers featuring cholesterol units as side-chain pendant groups, resulting in smectic-A (SmA) liquid crystal elastomers (LCEs). Foam-like scaffolds, prepared using metal templates, feature interconnected microchannels, making them suitable as 3D cell culture scaffolds. The combined properties of the regular structure of the metal foam and of the elastomer result in a 3D cell scaffold that promotes not only higher cell proliferation compared to conventional porous templated films, but also better management of mass transport (i.e., nutrients, gases, waste, etc.). The nature of the metal template allows for the easy manipulation of foam shapes (i.e., rolls or films) and for the preparation of scaffolds of different pore sizes for different cell studies while preserving the interconnected porous nature of the template. The etching process does not affect the chemistry of the elastomers, preserving their biocompatible and biodegradable nature. We show that these smectic LCEs, when grown for extensive time periods, enable the study of clinically relevant and complex tissue constructs while promoting the growth and proliferation of cells.

This study presents a methodology to prepare 3D, biodegradable, foam-like cell scaffolds based on biocompatible side-chain liquid crystal elastomers (LCEs). Confocal microscopy experiments show that foam-like LCEs allow for cell attachment, proliferation, and the spontaneous alignment of C2C12s myoblasts.

3D 공간 세포 배양을위한 세포 발판으로 생체 적합성 액정 엘라스토머 거품의 합성

Here, we present a step-by-step preparation of a 3D, biodegradable, foam-like cell scaffold. These scaffolds were prepared by cross-linking star block ...