Patterning of Microgel Particles on Polymer Surface Controlled by Autophobicity and Interfacial Tension

摘要

Autophobicity prevents long chains (P units) of a polymer melt from penetrating into a high-density polymer brush composed of chemically identical chains (N units). While the chemical identity of P and N are sufficiently (or identically) similar to yield athermal mixing, an entropic barrier can arise at the brush interface due to the limited mobility of the brush chains anchored to the solid surface. Penetration of P into the brush results in strong stretching of the polymer chains in the brush under a high entropic penalty -3 While the autophobicity between a dense polymer brush anchored to a flat solid surface and a polymer melt has been well studied,4-7 the autophobicity between the dense hair layer of a spherical nanoscale microgel particle and a chemically identical polymer melt has not yet been examined. On the other hand, an understanding of microgel morphology and particle interaction with a polymeric environment is of both technological and fundamental importance.8-12 In this work, we report our observation on the autophobicity between core-shell microgel particles and a homopolymer. The microgels are driven by autophobicity to migrate to the film surface, while the migration can be reversibly controlled by adjusting the polymer surface energy. Exploiting such control, we have designed a stamping method to achieve designer patterning of the microgels on the surface of a polymer film.