Controlling the structure of star-like copolymer microgels through the monomer chain length to modulate softness and deswelling

We demonstrate that the incorporation of OEGMA chains alters the internal polymer distribution in a complex way that depends on the chain length: short OEGMA chains mitigate the internal inhomogeneities between core and shell of PNIPAM-EGDMA microgels, resulting in particles that are overall softer. For longer OEGMA the morphology changes to an even more compliant star-like structure that does not collapse into a compact sphere even at high temperature. These results show how the internal microstructure and physico-chemical properties of soft colloids can be modulated in great details in copolymer networks, in light of applications exploiting their softness for the fabrication of functional materials.