Brownian Dynamics Simulations on Single Chain Conformation of Graft Polyampholytes in Good Solvents

doi:10.7503/cjcu20150708

Abstract

Abstract:

Ascribed to the coexistence of opposite charges on same chain, polyampholytes present novel conformational behavior. By means of Brownian dynamics simulations, the conformations of moderately grafted polyampholytes(GPA), whose backbone and branches are oppositely charged in equilibrium, were investigated in salt-free good solvents. The influences of backbone length, side chain number and charge density were analyzed. The results revealed that with enhancing the electrostatic interactions, conformational transition process of GPA was composed of four stages including coil, overlapping between backbone and side chains, segment collapsing and charge pairing. Differ from linear polyampholytes, the strength of additional steric and electrostatic repulsions between side chains in GPA varies with changing the molecular structure and affects the conformational transition. Due to solvation of good solvents, a re-extension of GPA chains occurs under strong electrostatic interactions to ensure the completion of quadrupoles paired by dipoles. Decreasing the backbone length or the charge fraction, or increasing the side chain number strengthens the repulsions and rigidifies the backbone, resulting in retardation of molecular collapse and intensification of chain re-extension.

Key words: Brownian dynamics simulation, Graft polyampholyte, Conformation, Good solvent, Molecular structure

CLC Number:

O631.1⁺2

TrendMD:

PU Binbin, CHEN Tao, WANG Liquan, ZHU Shasha. Brownian Dynamics Simulations on Single Chain Conformation of Graft Polyampholytes in Good Solvents[J]. Chem. J. Chinese Universities, 2016, 37(3): 587.

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