Mesoporous Hydrogels from Microemulsions and Similar Structures for Hydrogel-based Sensors

来自微乳液的介孔水凝胶和用于水凝胶传感器的类似结构

• 批准号: 382408767
• 负责人: Professor Dr.-Ing. Gerald Gerlach
• 金额: --
• 依托单位: Leibniz-Institut für Polymerforschung Dresden (IPF)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/382408767?language=en
• 关键词: Mesoporous; Hydrogels; Microemulsions; Similar; Structures

Hydrogels are crosslinked polymers with the ability of uptaking huge amounts of water. This characteristic behavior leads to an increase of the hydrogel volume. Thus, hydrogels are the proper materials for applications in sensors and actuators, especially since hydrogels can be employed for utilization in micro systems.The swelling of huge hydrogel volumes results in detectable forces which can either be measured by means of a sensor or work as actuator components. However, the diffusion properties of water and chemical species in the crosslinked polymer structure of the hydrogel affect the response characteristics. Hence, high sensitivity often goes along with long response times.A solution may be the employment of porous hydrogels which can accelerate the cooperative diffusion process. Porous hydrogels in hydrogel-based piezoresistive pH sensors showed remarkable improvements in our previous works. Here, the response time of a pH sensor based on an acrylic acid/acrylamide based hydrogel was reduced considerably. Also, the swelling degree of the hydrogel increased noticeably. However, the sensitivity of the sensor decreased due to a decreased stiffness of the hydrogel. For this previous work, porous layers were synthesized by using porogens which cause a phase separation during polymerization. The use of porogens yields materials with macroporosity. Due to the synthesis method, the adjustment of pore sizes and pore size distribution is insufficient though.A possible route for synthesizing hydrogel layers with defined pore geometry is a template method described as follows. Mixtures of organic phase, water and surfactant are prepared. Stable, transparent solutions with defined aggregate structures (micelles, cylindrical micelles, bicontinuous, lamellae, hexagonal and cubic phases) occur at certain compositions. By dissolving monomers or polymers in the aqueous or organic phase of the template solution, the aggregate structures can be used as templates for the synthesis of mesoporous hydrogels with different morphologies.By using this method, firstly, the template is defined before polymerization. Secondly, replacement of macropores with mesopores leads to a higher hydrogel volume in the total volume of the hydrogel layer. For these reasons, this template method can evolve to be the preferred route to produce fast-responsive and sensitive hydrogels for microsystems technology.

水凝胶是交联的聚合物，具有吸收大量水的能力。这种特征行为导致水凝胶体积的增加。因此，水凝胶是在传感器和执行器中应用的适当材料，尤其是因为可以在微型系统中利用水凝胶。巨大的水凝胶体积的肿胀会导致可检测力的溶胀会导致可检测力，这可以通过传感器或作用作为执行器组件来测量。然而，水凝胶的交联聚合物结构中水和化学物种的扩散特性会影响响应特征。因此，高灵敏度通常与较长的响应时间有关。解决方案可能是多孔水凝胶的使用，可以加速合作扩散过程。基于水凝胶的压电pH传感器中的多孔水凝胶在我们以前的工作中显示出显着改善。在这里，基于丙烯酸/丙烯酰胺基水凝胶的pH传感器的响应时间大大减少了。同样，水凝胶的肿胀程度明显增加。但是，由于水凝胶的刚度降低，传感器的灵敏度降低。对于先前的工作，使用Porogens合成多孔层，在聚合过程中导致相位分离。使用孔子会产生具有巨大性的材料。由于合成方法，孔径和孔径分布的调整不足。具有定义的孔几何形状合成水凝胶层的可能途径是一种模板方法，如下所示。制备有机相，水和表面活性剂的混合物。稳定，透明的溶液具有定义的骨料结构（胶束，圆柱胶束，双连续，薄片，六边形和立方相），出现在某些组合物处。通过将单体或聚合物溶解在模板溶液的水性或有机相中，可以将聚集体结构用作具有不同形态的中端水凝胶合成的模板。首先，使用此方法，模板是在聚合之前定义的。其次，用中孔代替大孔会导致水凝胶层的总体积较高。由于这些原因，这种模板方法可以发展为生产微型系统技术的快速响应和敏感水凝胶的首选途径。