Synergizing network topology and solvent compatibility for gels with hyperelasticity and omniadhesion.

Abstract

In polymeric gels, hyperelasticity and strong adhesion are often required but difficult to achieve simultaneously. Here we propose a principle of hyperelastic and omniadhesive gels composed of polymer networks with long dangling chains and sufficient good solvents. The molecules of good solvents screen off interchain interactions for hyperelasticity. The long dangling chains disentangle and adsorb to substrate for strong adhesion. We synthesized such gels by controlling the polymerization kinetics. When a monomer solution is partially cured, some monomers form a network and others form the solvent. The resulting gel, termed homogel, consists of a polymer network with enormous dangling chains and solvent of identical chemistries. An interval exists where the dangling chains are long and disentangled substantially, and the homogel exhibits both hyperelasticity and omniadhesion. We demonstrated such a gel with a hysteresis of 4.1% (stretch = 10) and adhesion energy of ~510 joules per square meter. The principle is generic and applicable to gels of different types.