Macromolecules paper: a new concept for stiffness changing soft matter

Our paper “Thermoresponsive stiffening with microgel particles in a semiflexible fibrin network” in collaboration with Schweizer and Braun groups (Material Science, Illinois) is now published in Macromolecules.

We introduce a new paradigm for designing soft materials with large changes of reversibly triggerable stiffness by combining semiflexible polymers that stiffen in tension with microgel polymer particles that massively deswell with heating.

Microgel colloidal particles of poly(N-isopropylacrylamide) (pNIPAM) are embedded in semiflexible biopolymer networks of fibrin. Individual components soften with temperature. When combined, the composite material modulus reversibly stiffens up to 10x in some cases. The developed micromechanical model quantifies the hypothesis of microgel-induced polymer network deformation and is consistent with experimental trends.