Designing protocols to dynamically direct the self-assembly of colloidal particles has become an important direction in soft matter physics because of promising applications in the fabrication of dynamic responsive functional materials. Here, using computer simulations, we found that in the mixture of passive colloids and eccentric self-propelled active particles, when the eccentricity and self-propulsion of active particles are high enough, the eccentric active particles can push passive colloids to form a large dense dynamic cluster, and the system undergoes a novel dynamic demixing transition. Our simulations show that the dynamic demixing occurs when the eccentric active particles move much faster than the passive particles such that the dynamic trajectories of different active particles can overlap each other while passive particles are depleted from the dynamic trajectories of active particles. Our results suggest that this is in analogy to the entropy-driven demixing in colloid–polymer mixtures, in which polymer random coils can overlap with each other while depleting the colloids. More interestingly, we find that by fixing the passive colloid composition at a certain value with increasing density, the system undergoes an intriguing re-entrant mixing, and the demixing only occurs within a certain intermediate density range. This suggests a new way of designing active matter to drive the self-assembly of passive colloids and fabricate dynamic responsive materials.

中文翻译：

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使用偏心自推进胶体驱动动态胶体组装

设计协议以动态地指导胶体粒子的自组装已成为软物质物理学的重要方向，因为在动态响应功能材料的制造中有希望的应用。在这里，通过计算机模拟，我们发现在被动胶体和偏心自推进活性颗粒的混合物中，当主动颗粒的偏心率和自推进力足够高时，偏心活性颗粒可以推动被动胶体形成大的致密性。动态簇，并且系统经历了新颖的动态混合过渡。我们的仿真表明，当偏心有源粒子的移动速度比无源粒子的移动快得多时，就会发生动态混合，从而使不同有源粒子的动态轨迹可以相互重叠，而无源粒子却从有源粒子的动态轨迹中消失了。我们的结果表明，这类似于胶体-聚合物混合物中的熵驱动分解，其中聚合物无规卷曲物可以相互重叠，同时消耗胶体。更有趣的是，我们发现通过将被动胶体组合物固定在一定的值上并增加密度，系统会产生有趣的凹角混合，并且仅在一定的中间密度范围内会发生分解。