Abbott Lauren J, Stevens Mark J
Sandia National Laboratories, Albuquerque, New Mexico 87185, USA.
J Chem Phys. 2015 Dec 28;143(24):244901. doi: 10.1063/1.4938100.
A coarse-grained (CG) model is developed for the thermoresponsive polymer poly(N-isopropylacrylamide) (PNIPAM), using a hybrid top-down and bottom-up approach. Nonbonded parameters are fit to experimental thermodynamic data following the procedures of the SDK (Shinoda, DeVane, and Klein) CG force field, with minor adjustments to provide better agreement with radial distribution functions from atomistic simulations. Bonded parameters are fit to probability distributions from atomistic simulations using multi-centered Gaussian-based potentials. The temperature-dependent potentials derived for the PNIPAM CG model in this work properly capture the coil-globule transition of PNIPAM single chains and yield a chain-length dependence consistent with atomistic simulations.
采用自上而下和自下而上相结合的方法，为热响应性聚合物聚（N-异丙基丙烯酰胺）（PNIPAM）开发了一种粗粒度（CG）模型。按照SDK（筱田、德瓦内和克莱因）CG力场的程序，将非键合参数拟合到实验热力学数据，并进行了微小调整，以使其与原子模拟得到的径向分布函数更好地吻合。使用基于多中心高斯的势将键合参数拟合到原子模拟的概率分布。在这项工作中为PNIPAM CG模型推导的温度相关势能够恰当地捕捉PNIPAM单链的线圈-小球转变，并产生与原子模拟一致的链长依赖性。
