Hydrogels possess highly attractive physicochemical properties that make them suitable for a wide range of biomedical applications. The tunable characteristics of hydrogels make them versatile and provide optimization for specific applications. Depending on the target use, various modification mechanisms may be required for the favorable performance of hydrogel constructs.
We present light switchable hydrogels that are able to change their geometry and / or hydrophilicity on the nanoscale, translating to a change of the Young’s modulus on the micro- and macroscale. Thus for this purpose PNIPAAm hydrogels functionalized with L-shaped spiropyrans that can be switched into the elongated, much more polar, highly colored merocyanines are synthesized and investigated using DSC UV-VIS and rheological analysis. An important aspect of this system is that the mechanical properties of the hydrogels can be controlled.