Self-Growing Polymer Gels with Tunable Swelling Properties

Self-growing polymers can be used as building blocks for materials having a wide range of desirable properties, e.g. self-healing, controllable gradient in material properties, programmable deformation etc. To this end, we present a minimalistic theoretical model of two types of self-growing polymer gels, one comprising of an interpenetrating network (IPN) of two parent-chains, and the other one consisting of a random copolymer network (RCN), with the copolymers being formed by an inter-chain exchange between the IPN units. When placed in a monomer solution, these gels exhibit sustained growth by assimilating monomeric units from the solution into their network. We show how this swelling could be controlled by tuning the cross-link density as well as the chemical properties of the monomer and solvent units in the ambient solution.