Scattering functions of knotted ring polymers

We discuss the scattering function of a Gaussian random polygon with N nodes under a given topological constraint through simulation. We obtain the Kratky plot of a Gaussian polygon of N=200 having a fixed knot for some different knots such as the trivial, trefoil and figure-eight knots. We find that some characteristic properties of the different Kratky plots are consistent with the distinct values of the mean square radius of gyration for Gaussian polygons with the different knots.Comment: 4pages, 3figures, 3table

Effects of hydrodynamic interactions on a coil-globule transition of a single polymer(Poster session 2, New Frontiers in Colloidal Physics : A Bridge between Micro- and Macroscopic Concepts in Soft Matter)

この論文は国立情報学研究所の電子図書館事業により電子化されました。ソフトマターは,系の内部に溶媒を含んでいるため,流体を介した相互作用がそのダイナミクスに大きく影響している.本研究では,この流体力学的相互作用を取り入れたシミュレーション手法を用いて,流体が高分子鎖のコイル-グロビュール転移において果たす役割について明らかにすることを目的とする.我々は,様々な慣性半径を持つ初期配置からの凝縮ダイナミクスを扱った.その結果,高分子鎖の初期配置によって流体は,大きく分けて2つの働きをすることがわかった.A polymer immersed in a solvent begins to collapse from an expanded to a compact globule state, when the solvent quality changes from good to poor. This phenomenon is known as a coil-globule transition. The static property of this transition has been well understood theoretically and experimentally. Because of experimental difficulties, however, its dynamics is less understood. Since a coil-globule transition is regarded as a model of a protein folding, the understanding of the transition is also highly desired from the viewpoint of biophysics

The Development to Control Simultaneously Viscosity and Separation Temperature of a Two Phase Lubricant for Practical Use

Fuel economy is a major challenge for the automotive industry. A key way to improve lubricant fuel efficiency is by using polymers as viscosity index improvers to maximise the viscosity index of the lubricants. The viscosity index of automotive lubricants has an upper limit of around 250 because usage of high treat rates can lead to shear stability and flash point issues. To overcome this, the concept of two phase lubricants was reported in former literature but the practical application had not been examined. In this paper, the practical application with an additional ability to control viscosity and separation temperature simultaneously of a two phase lubricant is reported. It is possible to formulate a two phase lubricant with mineral or synthetic base oil and polyalkylene glycol to achieve viscosity index of 500 and keeping the properties of shear stability and flash point on a competitive level as of commercial single phase lubricants. Also, there is little evidence of issues with the lubrication properties. It was shown that additions of Di-isononyl adipate acting as a control element simultaneously control the viscosity and separating temperature of the two phase lubricants