Inspired by elastomers: fabrication of hydrogels with tunable properties and re-shaping ability via photo-crosslinking at a macromolecular level†
Abstract
Conventional hydrogels cross-linked by small molecular cross-linkers usually exhibit poor mechanical properties, limiting the application of hydrogels to a certain degree. Here, inspired by the fabrication technologies of elastomers, we firstly fabricate a macromolecular hydrogel pre-polymer (MHP) via thermal polymerization and then crosslink the MHP at a macromolecular level by UV irradiation. In this novel technology, polyetheramine (PEA) plays an important role in the fabrication of crosslinked hydrogels. In the thermal polymerization stage, N–CH3 units in PEA acted as co-initiators and grafting agents to form an MHP. Under the UV irradiation, benzophenone (BP) moieties in PEA could be excited as photo-cross-linkers. More importantly, the tensile stress of PEA5%-PAAm hydrogel could be effectively tailored from 180 kPa to 500 kPa by controlling the crosslinking degree under different irradiation times. Through this important characteristic, we could also effectively build a hydrogel with a complex three dimensional (3D) geometry, which is not easily obtained by conventional polymerization methods.