Multiscaled density-functional theory for helical polymers.
We propose a density-functional theory (DFT) for helical polymers by introducing the orientational potential of a molecule. A multiscaled finite element approach is incorporated to reduce the time consumption of the computation efficiently. The multiscaled finite element approach proposed here can be easily applied to the calculations of different versions of DFTs. The agreements of the calculated results and Monte Carlo data in studying flexible and rodlike polymers confirm that our approach does lead to correct predictions. By using the proposed theory, we explore the self-assembly of helical polymers on a hydrophobic surface. The dependences of density profiles and orientational distributions on the helical conformation and the attractive strength of the surface are also investigated. It is found that a homeotropic monolayer would be formed on the surface directly as the ratio between helical radii (R) and height (H) is less than 0.5. At the range of 0.5 < or = R/H < 1, a planar homogeneous monolayer would be first formed at low attractive strength and then transmitted to a homeotropic monolayer at high attractive strength. For the case of R/H > or = 1, the helical polymers only assemble into the planar homogeneous monolayer with no transition to the homeotropic monolayer. Finally, we studied the effect of the helical conformation on the self-assembly by changing the helix angle from 75 degrees to 0 degrees. It is found that the helical conformation makes the polymers more difficult for the self-assembly compared to the noncoiled structures.
Xu
Xiaofei
X
Division of Molecular and Materials Simulation, Key Laboratory for Nanomaterials, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China.
Cao
Dapeng
D
D003198:Computer Simulation; D008958:Models, Molecular; D011108:Polymers / Q000737:chemistry*; D011789:Quantum Theory
D011108:Polymers