Self-Assembly and Nonlinear Viscoelasticity of ABC Triblock Copolymer-Based Patchy Nanoparticle Gels

Patchy nanoparticles constructed from block copolymers offer a versatile platform for creating polymer gels with programmable networks. Here, we employed dissipative particle dynamics simulations to investigate the self-assembly and nonlinear viscoelasticity of the gels formed by ABC triblock copolymer-based patchy nanoparticles. Cross-linking A-block micelle cores generates multifunctional patchy nanoparticles with tunable patch numbers determined by the length and rigidity of B-midblocks. These structural parameters modulate the steric shielding of C-block patches, thereby regulating nanoparticle functionality, gelation kinetics, and network topology. We revealed that, distinct from classical Flory gelation, each patch on a nanoparticle can interact with multiple neighboring patches, lowering the critical reaction extent. By coupling oscillatory shear simulations with Lissajous curve decomposition, we quantified the strain-softening behavior and identified the transition between elastic-dominated and viscous-dominated regimes. Time-dependent bond dynamics and mean-square displacement further elucidate the energy dissipation arising from reversible interparticle bonding and chain relaxation. Finally, comparison with gels obtained from direct self-assembly of ABC triblock copolymers demonstrated that the cross-linked cores endow gels with significantly enhanced modulus, structural robustness, and frequency stability. This work establishes molecular design principles for engineering high-performance polymer gels.