针对高分子刷构象转变的自振荡模型

Self-oscillation model of switching for polymer brushes

自振荡高分子刷在封闭空间中具有独特的应用.长期以来,由于缺乏理论模型,自振荡高分子刷的物理机制无法被深刻地揭示,其新结构也无法被预测.基于扩散动力学建立高分子刷自振荡的动力学理论模型,通过理论模型方程计算高分子刷的体积分数、高分子单体与溶剂相互作用的势函数,定量确定高分子刷构象转变自振荡的动力学特性,以及高分子单体的Belousov-Zhabotinsky(BZ)反应在诱导高分子刷自振荡过程中的重要作用,获得了高分子刷构象转变的化学波特性,揭示了这种化学波在很大程度上源于BZ反应.理论结果揭示了BZ反应导致化学振荡,在高分子刷内的扩散也是以化学波形式传播,且自振荡的高分子刷还可改变BZ的反应模式.研究结果确定了高分子刷的构象转变的自振荡特性遵守扩散动力学规律.基于所提模型可预言高分子刷体积分数的空间波动特性会导致刷内高分子单体体积分布具有空间不均匀性,令高分子刷内出现结节状结构.研究结果可为设计智能高分子表面材料提供参考.

Self-oscillating polymer brushes have unique applications in enclosed spaces,but there has been a lack of theoretical model to reveal their physical mechanisms systematically and profoundly and predict new structures.Based on diffusion dynamics,we establish a new theoretical model to study the self-oscillation of switching for polymer brushes.Firstly,we quantitatively determine the dynamic characteristics of self-oscillation switching of polymer brush as well as the important role of the Belousov Zhabotinsky(BZ)reaction of polymer monomers in inducing polymer brush self-oscillation.Then,the chemical wave characteristics of the conformational transition of the polymer brush are obtained,revealing that this chemical wave largely originated from the BZ reaction.The theoretical results reveal that the BZ reaction lead to chemical oscillations,and the diffusion within the polymer brush also propagates in the form of chemical waves. Moreover, the self-oscillating polymer brush can also change the reaction mode of BZ. The research results confirm that the self-oscillating characteristics of the conformational transition of the polymer brush follow diffusion dynamics. Based on the model, it can be predicted that the spatial fluctuation of the volume fraction of polymer brushes will lead to the spatial non-uniformity of volume distribution of polymer monomers in the brushes, and then a nodular structure will appear in the polymer brushes. The results of this paper can provide useful reference for designing intelligent polymer surface materials.