Rational Design of Strain-Adaptive Elastomers through Polymer Architectures

Designing materials capable of mimicking the mechanical properties of soft biological tissues is important for tissue engineering, soft robotics, and wearable electronics. The biological tissues show a unique combination of the mechanical softness and strong strain-stiffening, which make it difficult to replicate in synthetic elastomers composed of linear polymers. Using a combination of theoretical calculations and molecular dynamics simulations, we have developed a universal materials design strategy which encodes the stress-strain curve of soft materials into the molecular architecture of graft polymer networks. Such networks can be made either by chemical crosslinking of graft polymer strands or by self-assembly of linear-bottlebrush-linear triblock copolymers. The mechanical response of such networks is controlled by the architectural parameters (i.e. network strand length, side chain length, grafting density, and composition of triblock copolymers). Our approach is verified by synthesizing PDMS networks of combs and bottlebrushes with mechanical properties of jellyfish, lung, and arterial tissue. This technique lays the foundation for computationally driven design of soft materials.