Figure 4.

Adaptive surfaces based on photoresponsive hydrogels. A) Scheme showing the reversible switching of striped chemical patterns induced by exposure of PNIPAM hydrogels loaded with iron oxide nanoparticles to visible light. Reproduced with permission.¹¹⁸ Copyright 2019, Wiley‐VCH. B) Schematic illustration of light‐regulated molecular diffusion across a hydrogel layer based on the photoisomerization of spiropyran. Reproduced under the terms of the CC‐BY Creative Commons Attribution 3.0 Unported Licence ().¹²⁰ Copyright 2019, Royal Society of Chemistry. C) Schematic illustration of regulated protein adhesion by phototriggered charge change on a hydrogel surface. Reproduced with permission.¹²² Copyright 2019, Wiley‐VCH.