Jiang Shulan, Xia Li
School of Mechanical Engineering and Electronic Information, China University of Geosciences (Wuhan), Wuhan 430074, China.
Tribology Research Institute, School of Mechanical Engineering, Southwest Jiaotong University, Chengdu 610031, China.
Polymers (Basel). 2022 Oct 19;14(20):4425. doi: 10.3390/polym14204425.
Soft actuators have attracted extensive attention for promising applications in drug delivery, microfluidic switches, artificial muscles and flexible sensors. However, the performance of pH-responsive hydrogel actuators, such as regarding reversible bending property and adhesive property, remains to be improved. In this study, inspired by drosera leaves, we have fabricated high-performance bilayer, pH-responsive poly(acrylamide-acrylic acid-3-acrylamidophenylboronic acid)(P(AAm-AAc-3-AAPBA)) based on the copolymers of AAm, AAc and 3-AAPBA. The pH-sensitive actuators were fabricated by ultraviolet polymerization of the P(AAm-AAc-3-AAPBA) layer as the active actuating layer and the PAAm layer as the auxiliary actuating layer. The effects of pH, glucose concentration and content of 3-AAPBA on bending behavior of P(AAm-AAc-3-AAPBA)/PAAm bilayer actuators were discussed. By tuning the pH of media, the soft actuator could achieve fast and large-amplitude bidirectional bending behaviors. The bending orientation and bending degree can be reversibly and precisely adjusted. More importantly, P(AAm-AAc-3-AAPBA) hydrogel shows good adhesive property in polyvinyl alcohol (PVA) solution; thus, complex structures have been fabricated. In addition, the bilayer hydrogel structures have been demonstrated as soft actuators, bionic flowers and bionic manipulators. The proposed pH-responsive bilayer actuator shows great potential for drug delivery and other medical systems.
软驱动器因其在药物输送、微流体开关、人造肌肉和柔性传感器等领域的应用前景而备受关注。然而，pH响应水凝胶驱动器的性能，如可逆弯曲性能和粘附性能，仍有待提高。在本研究中，受茅膏菜叶子的启发，我们基于丙烯酰胺（AAm）、丙烯酸（AAc）和3-丙烯酰胺基苯硼酸（3-AAPBA）的共聚物，制备了高性能双层pH响应性聚（丙烯酰胺-丙烯酸-3-丙烯酰胺基苯硼酸）（P（AAm-AAc-3-AAPBA））。pH敏感驱动器是通过将P（AAm-AAc-3-AAPBA）层作为活性驱动层，聚丙烯酰胺（PAAm）层作为辅助驱动层进行紫外光聚合制备的。讨论了pH值、葡萄糖浓度和3-AAPBA含量对P（AAm-AAc-3-AAPBA）/PAAm双层驱动器弯曲行为的影响。通过调节介质的pH值，软驱动器可以实现快速、大幅度的双向弯曲行为。弯曲方向和弯曲程度可以可逆且精确地调节。更重要的是，P（AAm-AAc-3-AAPBA）水凝胶在聚乙烯醇（PVA）溶液中表现出良好的粘附性能；因此，制备了复杂结构。此外，双层水凝胶结构已被证明可作为软驱动器、仿生花和仿生操纵器。所提出的pH响应双层驱动器在药物输送和其他医疗系统中显示出巨大潜力。
