离子模板交联法调控聚乙烯醇/海藻酸钠水凝胶的可控变形行为

Controllable Transformations of Strong Polyvinyl Alcohol/Sodium Alginate Hydrogels via Ionic Crosslink Lithography

设计了一种通用的离子模板交联法制备了物理交联高强度聚乙烯醇/海藻酸钠(PVA/SA)水凝胶,并可能通过可控的方式实现PVA/SA水凝胶的三维空间变形。对同一块水凝胶选择性交联,利用PVA/SA和PVA/SA/Fe^(3+)水凝胶具有显著的溶胀性差异的特点,通过两步法引导图案化水凝胶局部溶胀和整体弯曲,发生可控变形,得到特定的多样构型。同时,由于水凝胶网络中离子配位具有可逆性,此变形是可逆可重复的。进一步在3D打印中构建在平面梯度和厚度梯度具有各向异性的水凝胶,可实现螺旋、弯曲等可控变形。

A versatile ionic crosslink lithography method was designed to prepare strong physically cross-linked polyvinyl alcohol/sodium alginate(PVA/SA)hydrogels and the three-dimensional deformation in a control-lable manner was achieved.For the selective cross-linking,the localized PVA/SA and PVA/SA/Fe^(3+)hydrogel do-mains with significant differences in swellabilities in a PVA/SA hydrogel sheet.According to a simple 2-step se-quential pre-and free-swelling,the patterned hydrogel sheet could be directed to a controllable transformation and specific configurations through local bulging and/or global buckling.This type of shape changing is reversible and repeatable due to the reversibility of ionic coordination in the hydrogel networks.Further,a hydrogel with anisotro-py in plane gradient and thickness gradient could be constructed to achieve controllable deformation such as helix and bending in 3D printing.This ionic crosslink lithography method developed in this work may have certain appli-cation prospects in the development of wearable software sensors and software drivers,and it provides reference for the further development and application of hydrogels.