Non-affinity of liquid networks and bicontinuous mesophases

Michael S. Dimitriyev; Xueyan Feng; Edwin L. Thomas; Gregory M. Grason

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arXiv · 2311.07544

Non-affinity of liquid networks and bicontinuous mesophases

Michael S. Dimitriyev·Xueyan Feng·Edwin L. Thomas·Gregory M. Grason

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Abstract

Amphiphiles self-assemble into a variety of bicontinuous mesophases whose equilibrium structures take the form of high-symmetry cubic networks. Here, we show that the symmetry-breaking distortions in these systems give rise to anomalously large, non-affine collective deformations, which we argue to be a generic consequence of mass equilibration within deformed networks. We propose and study a minimal liquid network model of bicontinuous networks, in which acubic distortions are modeled by the relaxation of residually-stressed mechanical networks with constant-tension bonds. We show that non-affinity is strongly dependent on the valency of the network as well as the degree of strain-softening/stiffening force in the bonds. Taking diblock copolymer melts as a model system, liquid network theory captures quantitative features of two bicontinuous phases based on comparison with self-consistent field theory predictions and direct experimental characterization of acubic distortions, which are likely to be pronounced in soft amphiphilic systems more generally.

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Michael S. Dimitriyev, Xueyan Feng, Edwin L. Thomas, Gregory M. Grason. 2023-11-13. Non-affinity of liquid networks and bicontinuous mesophases. https://arxiv.org/abs/2311.07544

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