采用非格点珠簧球链模型,结合Monte Carlo方法,研究了半刚性高分子链受限于无限长圆柱体的构象性质.模拟结果表明:在圆柱体内表面附近具有吸附能的情况下,当弯曲能b由小到大变化时,发现半刚性高分子链由开始时的无规则被吸附在圆柱体内表面,到逐渐出现螺旋结构,最后伸展成类似棒状的结构.同时计算了不同弯曲能b时的半刚性高分子链的平均螺旋数N_t,平均每条链单体的螺旋百分比P_h和能量涨落.发现高分子链螺旋结构的形成与转变,不仅与圆柱体半径R的大小有关,还与弯曲能b的大小有关.研究结果能有助于加深对受限生物大分子构象的认识.
In this paper we use an off-lattice bead-spring model to study the behaviors of polymer chain confined in an infinite cylinder by Monte Carlo simulations. Our simulation results show that when the bending energy b increases in the presence of the adsorption energy of the inner-surface of cylinder, the polymer chain is first randomly attracted on the inner surface of cylinder, and then gradually takes on helix structure, and finally is stretched into the rod-like structure. In order to understand the process of structure transition of polymer chain, we calculate the average of number of helical turns per chain Nt, the average percentage Ph of beads of helical structure per chain and the energy fluctuations with different values of bending energy b. The confined semirigid chain can form helical structure with the appropriate bending energy and the proper radius of cylinder. This study can help us understand the conformational behaviors of biopolymers in confined space.