Liu Ya, Aizenberg Joanna, Balazs Anna C
Chemical and Petroleum Engineering Department, University of Pittsburgh, Pittsburgh, PA 15261, USA.
Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA.
Nanomaterials (Basel). 2021 Oct 19;11(10):2764. doi: 10.3390/nano11102764.
Computational models that reveal the structural response of polymer gels to changing, dissolved reactive chemical species would provide useful information about dynamically evolving environments. However, it remains challenging to devise one computational approach that can capture all the interconnected chemical events and responsive structural changes involved in this multi-stage, multi-component process. Here, we augment the dissipative particle dynamics (DPD) method to simulate the reaction of a gel with diffusing, dissolved chemicals to form kinetically stable complexes, which in turn cause concentration-dependent deformation of the gel. Using this model, we also examine how the addition of new chemical stimuli and subsequent reactions cause the gel to exhibit additional concentration-dependent structural changes. Through these DPD simulations, we show that the gel forms multiple latent states (not just the "on/off") that indicate changes in the chemical composition of the fluidic environment. Hence, the gel can actuate a range of motion within the system, not just movements corresponding to the equilibrated swollen or collapsed states. Moreover, the system can be used as a sensor, since the structure of the layer effectively indicates the presence of chemical stimuli.
能够揭示聚合物凝胶对不断变化的溶解活性化学物质的结构响应的计算模型，将提供有关动态演化环境的有用信息。然而，设计一种能够捕捉这个多阶段、多组分过程中所有相互关联的化学事件和响应性结构变化的计算方法，仍然具有挑战性。在这里，我们扩展了耗散粒子动力学（DPD）方法，以模拟凝胶与扩散的溶解化学物质反应形成动力学稳定络合物的过程，而这些络合物又会导致凝胶发生浓度依赖性变形。使用这个模型，我们还研究了添加新的化学刺激物和随后的反应如何使凝胶表现出额外的浓度依赖性结构变化。通过这些DPD模拟，我们表明凝胶形成了多种潜在状态（不仅仅是“开/关”状态），这些状态表明了流体环境化学成分的变化。因此，凝胶可以在系统内引发一系列运动，而不仅仅是对应于平衡溶胀或收缩状态的运动。此外，该系统可以用作传感器，因为层的结构有效地表明了化学刺激物的存在。
