Collaborative Research: Microfabrication and Self-Assembly of Shape-Changing Hydrogels with Chromonic Liquid Crystalline Order

合作研究：彩色液晶有序变形水凝胶的微加工和自组装

• 批准号: 1663367
• 负责人: Taylor Ware
• 金额: $ 17.57万
• 依托单位: University of Texas at Dallas
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2020-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1663367&HistoricalAwards=false
• 关键词: Collaborative; Research; Microfabrication; Self; Assembly

Shape-changing liquid crystal hydrogels are soft, rubbery materials that can perform mechanical work as "artificial" muscles, without motors, joints, or control systems. They move spontaneously in response to slight temperature changes, and can be designed to flex in different geometries. This collaborative research effort focuses on developing techniques to engineer these materials to produce novel devices such as self-cleaning surfaces. Like the cilia that sweep contaminants from human lungs, surfaces will be coated with micro-scale hydrogel structures that move as temperature fluctuates. These novel active coatings will address a critical need for self-cleaning devices in healthcare applications, and could prevent bacterial contamination that leads to frequent infections and thousands of deaths annually in the United States. In addition, community outreach efforts will be designed that engage young students and will help to broaden the diversity of the technical workforce, and research internships will help prepare high school students for advanced studies in science and engineering. Smart, programmable materials that respond mechanically to environmental stimuli are needed for smart biomedical devices. Hydrogels with chromonic liquid crystalline order are of interest for such applications because they morph anisotropically in response to biologically-benign temperature changes, and because their actuation trajectory can be programmed by patterning the material's molecular alignment. A key challenge is to fabricate such complex actuators at length scales too small to access via 3D printing and in shape profiles that are not flat films. This award supports development of novel techniques for design and microfabrication of shape-morphing hydrogels, using hierarchical patterning of molecular orientation achieved by combining soft lithography and liquid crystal self-assembly. This fundamental research will test the hypothesis that the shape of soft lithography molds can be used to pattern molecular alignment in micro-scale structures made of chromonic liquid crystal hydrogels, and that these aligned hydrogels can undergo programmable actuation in response to biologically-benign temperature changes. This processing approach will be used to create artificial cilia-like structures. Experimental efforts will be closely coupled to theory/simulation at two levels. First, the molecular order (nematic director) arising from surface anchoring from the soft lithography mold and liquid crystal chirality will be modeled. Second, nonlinear finite element elastodynamics simulations will be used to model shape evolution of active hydrogel micro-devices with a given director field as they transform under stimulus. This collaborative project brings together a multidisciplinary team with complementary expertise in responsive materials chemistry, materials modeling, and mechanical design.

形状可变的液晶水凝胶是柔软的橡胶材料，可以像“人造”肌肉一样进行机械工作，没有马达，关节或控制系统。它们会自发地响应轻微的温度变化，并可以设计成不同的几何形状。这项合作研究工作的重点是开发技术，以工程这些材料生产新的设备，如自清洁表面。就像纤毛清除人类肺部的污染物一样，表面将被覆盖上微尺度的水凝胶结构，随着温度的波动而移动。这些新型活性涂层将满足医疗保健应用中对自清洁设备的关键需求，并可以防止细菌污染，导致美国每年发生频繁感染和数千人死亡。此外，将设计社区外联工作，让青年学生参与，并将有助于扩大技术劳动力的多样性，研究实习将有助于高中生为科学和工程方面的深造做好准备。智能生物医学设备需要对环境刺激做出机械响应的智能可编程材料。具有有色液晶有序的水凝胶对于此类应用是令人感兴趣的，因为它们响应于生物学上良性的温度变化而各向异性地变形，并且因为它们的致动轨迹可以通过图案化材料的分子排列来编程。一个关键的挑战是制造这种复杂的致动器，其长度尺度太小，无法通过3D打印访问，并且形状轮廓不是平坦的薄膜。该奖项支持开发用于形状变形水凝胶的设计和微制造的新技术，使用通过结合软光刻和液晶自组装实现的分子取向的分层图案化。这项基础研究将测试的假设，即软光刻模具的形状可用于图案化的分子排列在由有色液晶水凝胶制成的微尺度结构，这些对齐的水凝胶可以进行可编程的驱动响应于生物良性的温度变化。这种处理方法将用于创建人工纤毛状结构。实验工作将在两个层面上与理论/模拟紧密结合。首先，将模拟由软光刻模具的表面锚定和液晶手性产生的分子有序（指向矢）。第二，非线性有限元弹性动力学模拟将用于模拟具有给定指向矢场的活性水凝胶微器件在刺激下变换时的形状演变。这个合作项目汇集了一个多学科团队，在响应材料化学，材料建模和机械设计方面具有互补的专业知识。

项目成果

Emergent Surface Topography Enabled by Concurrent Crystallization and Polymerization

通过同时结晶和聚合实现新兴表面形貌

• DOI: 10.1021/acs.macromol.9b02703
• 发表时间: 2020
• 期刊: Macromolecules
• 影响因子: 5.5
• 作者: Abdelrahman, Mustafa K.;Kim, Hyun;Maeng, Jimin;Ondrusek, Patrick;Ware, Taylor H.
• 通讯作者: Ware, Taylor H.

Shape-morphing living composites

• DOI: 10.1126/sciadv.aax8582
• 发表时间: 2020-01
• 期刊: Science Advances
• 影响因子: 13.6
• 作者: Laura K. Rivera‐Tarazona;Vandita D Bhat;Hyun Kim;Z. Campbell;T. Ware

Molecularly-ordered hydrogels with controllable, anisotropic stimulus response

• DOI: 10.1039/c9sm00763f
• 发表时间: 2019-06-14
• 期刊: SOFT MATTER
• 影响因子: 3.4
• 作者: Boothby, Jennifer M.;Samuel, Jeremy;Ware, Taylor H.
• 通讯作者: Ware, Taylor H.