高分子刷诱导的纳米棒取向转变.docVIP

  Orientation transition of nanorods induced by polymer brushes# ZHANG Dong, ZHANG Linxi** 5 10 15 20 25 30 35 (Department of Physics, Zhejiang University, HangZhou 310027) Abstract: Coarse-grained molecular dynamics simulations were employed to explore the spatial orientation transitions of NRs induced by the semiflexible polymer brushes in this work. By enhancing the length of NRs or the attractive strength between NRs and polymer brushes, the NRs will experience a transition from vertically orientation to horizontally orientation under the effect of torque caused by the difference in monomers density of polymer brush between two NR ends. And we also found that the higher the grafting density is, the difficult the orientation transition of NR is. Our results may be helpful in biological engineering and materials science fields. Keywords: nanorod; polymer brush; orientation transition; molecular dynamics simulation 0 Introduction Polymer brushes, which are dense layers of polymer chains grafted by one or two chain ends to a non-adsorbing substrate surface, have attracted a tremendous of attentions nowadays because of its numerous important applications such as the improvement of lubrication properties of surfaces, colloid stabilization, the biocompatibility of drugs, tuning of adhesion and wetting properties of surfaces, creation of protective coatings preventing the protein adsorption in a biological environment, microfluidic devices for biomolecules separation, and so on. Furthermore, the nanoinclusions in polymer brushes (nanoparticles, nanorods, metallic, semiconducting, colloids, oligomers, linear macromolecules, solvent molecules, proteins, etc.) not only correspond to some natural systems, for example, mammalian synovial joints, capillaries in plants or bloodstream, and thus it is very important in bioengineering fields, e.g., the tuning or inhibiting protein adsorption and cell adhesion; but also as “designer molecules”, hold great promise for the deve