ITMO University, 49 Kronverksky Prospekt, Saint Petersburg, 197101, Russia.
Institute of Macromolecular Compounds, Russian Academy of Sciences, 31 Bolshoy Prospect, Saint Petersburg, 199004, Russia.
Macromol Rapid Commun. 2023 Aug;44(16):e2200980. doi: 10.1002/marc.202200980. Epub 2023 Mar 29.
Polymer brushes are attractive as surface coatings for a wide range of applications, from fundamental research to everyday life, and also play important roles in biological systems. How colloids (e.g., functional nanoparticles, proteins, viruses) bind and move across polymer brushes is an important yet under-studied problem. A mean-field theoretical approach is presented to analyze the binding and transport of colloids in planar polymer brushes. The theory explicitly considers the effect of solvent strength on brush conformation and of colloid-polymer affinity on colloid binding and transport. The position-dependent free energy of the colloid insertion into the polymer brush which controls the rate of colloid transport across the brush is derived. It is shown how the properties of the brush can be adjusted for brushes to be highly selective, effectively serving as tuneable gates with respect to colloid size and affinity to the brush-forming polymer. The most important parameter regime simultaneously allowing for high brush permeability and selectivity corresponds to a condition when the repulsive and attractive contributions to the colloid insertion free energy nearly cancel. This theory should be useful to design sensing and purification devices with enhanced selectivity and to better understand mechanisms underpinning the functions of biological polymer brushes.
聚合物刷作为表面涂层在广泛的应用中具有吸引力，从基础研究到日常生活，并且在生物系统中也起着重要的作用。胶体（例如功能纳米粒子、蛋白质、病毒）如何在聚合物刷上结合和移动是一个重要但研究不足的问题。本文提出了一种平均场理论方法来分析胶体在平面聚合物刷中的结合和输运。该理论明确考虑了溶剂强度对刷状构象的影响以及胶体-聚合物亲和力对胶体结合和输运的影响。推导了控制胶体穿过刷状结构传输速率的胶体插入聚合物刷的位置相关自由能。展示了如何调整刷的性质，使其具有高选择性，有效地作为可调谐门，以适应胶体的大小和对形成聚合物刷的亲和力。同时允许高刷渗透性和选择性的最重要参数范围对应于胶体插入自由能的排斥和吸引贡献几乎抵消的条件。该理论应该有助于设计具有增强选择性的传感和净化装置，并更好地理解生物聚合物刷功能的基础机制。
