Department of Chemical Engineering , Ryerson University , 350 Victoria Street , Toronto , Ontario M5B 2K3 , Canada.
Keenan Research Centre for Biomedical Science , St. Michael's Hospital , 30 Bond Street , Toronto , Ontario M5B 1W8 , Canada.
Langmuir. 2018 Jun 12;34(23):6856-6860. doi: 10.1021/acs.langmuir.8b00653. Epub 2018 Jun 4.
Environment-responsive hydrogel structures are of great interest in materials research and have a wide range of applications. By using a flow lithography technique, we report a one-step and high-throughput fabrication method for the synthesis of highly pH-responsive hydrogels with designed shape transformations. In this method, heterogeneous hydrogels with porous and nonporous layers are synthesized using a single UV exposure in a microfluidic channel. During the UV polymerization, the porous layers, which are formed by using polymerization-induced phase separation (PIPS), significantly increase the swelling capability and enhance the swelling rate of the hydrogels. Because the flow-lithography approach allows various patterns of porous/nonporous layers with great control and enables the simple integration of PIPS, resultant layered hydrogels show extraordinary deformations with desired pH response. More importantly, our fabrication approach can not only make 2D deformation of hydrogel structures such as bending but also can achieve 3D structural deformation such as helical and buckling structures, enabled by nonuniform UV polymerization we developed.
环境响应水凝胶结构在材料研究中具有重要意义，并且具有广泛的应用。通过使用流动光刻技术，我们报告了一种一步法和高通量制造方法，用于合成具有设计形状转变的高度 pH 响应水凝胶。在该方法中，使用微流道中的单次 UV 暴露合成具有多孔和无孔层的异质水凝胶。在 UV 聚合过程中，通过聚合诱导相分离（PIPS）形成的多孔层显著提高了水凝胶的溶胀能力并提高了其溶胀速率。由于流光刻方法允许对具有良好控制的多孔/无孔层进行各种图案的设计，并且能够简单地集成 PIPS，因此所得的层状水凝胶表现出具有所需 pH 响应的非凡变形。更重要的是，我们的制造方法不仅可以使水凝胶结构发生 2D 变形，例如弯曲，而且还可以通过我们开发的不均匀 UV 聚合来实现 3D 结构变形，例如螺旋和屈曲结构。
