刷介导的角约束重塑胶体脱嵌凝胶的结构、刚性和渗透性
Brush-mediated angular constraints reshape structure, rigidity, and percolation in colloidal depletion gels
AI总结：
研究通过降低表面接枝聚合物刷密度，引入非中心力，改变胶体凝胶的结构和机械特性，提升弹性模量。
摘要：
胶体凝胶，如同其他软而无序固体，其机械性能不仅来源于粒子间作用力的强度，还来源于约束粒子运动的力的对称性。虽然非中心相互作用已深刻改变刚性和弹性，但通常通过粒子各向异性、表面粗糙度或斑状相互作用引入，掩盖了其独立作用。本文展示了一种最小化且几何保持的途径，在胶体凝胶中产生新兴的非中心力，通过降低表面接枝聚合物刷的密度。在低刷密度下，部分刷子相互穿透在粒子接触处引入有效角弯曲刚性，尽管粒子几何完全各向同性。这种新兴约束抑制局部致密化，稳定低配位网络，并产生具有增强弹性的高度分叉凝胶结构。结合实验、模拟和平均场理论，我们显示这些非中心约束在不同长度尺度上重新组织结构和力学，移动凝胶化边界，并将弹性模量提高近三倍。我们的结果确立了表面刷密度作为软颗粒物质中编程相互作用对称性的通用控制参数，对无序系统中的刚性、渗透性和机械设计有影响。
英文摘要：
Colloidal gels, like many other soft and disordered solids derive their mechanical properties not only from the strength of interparticle attraction, but also from the symmetry of the forces that constrain particle motion. While non-central interactions are known to profoundly alter rigidity and elasticity, they are typically introduced through particle anisotropy, surface roughness, or patchy interactions, obscuring their independent role. Here we demonstrate a minimal and geometry-preserving route to emergent non-central forces in colloidal gels by reducing the density of surface-grafted polymer brushes. At low brush density, partial brush interpenetration introduces an effective angular bending rigidity at particle contacts, despite fully isotropic particle geometry. This emergent constraint suppresses local densification, stabilizes low-coordination networks, and produces highly ramified gel structures with enhanced elasticity. Combining experiments, simulations, and mean-field theory, we show that these non-central constraints reorganize structure and mechanics across length scales, shifting gelation boundaries and increasing the elastic modulus by nearly a factor of three. Our results establish surface brush density as a generic control parameter for programming interaction symmetry in soft particulate matter, with implications for rigidity, percolation, and mechanical design in disordered systems.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
