Self-consistent Field Theory Study On The Phase Separation And Gelation Transition In Physically Associating Polymer Solution

Polymer solution phase separation and gelation transition always polymer science domain interesting topic. As a result of polymer to the temperature sensitivity, we can regulate temperature in order to separate polymer from mixing solution by the stage separation. Therefore phase separation have widely applications for polymer purified experiments and industries production. Gelation is very important in polymer material domain. It has many excellent function. Sol-gel transition always polymer science extremely active topic, especially sol-gel method in chemistry sample preparation and actual production have widespread application. So polymer solution phase separation and sol-gel transition theory research is very significant. Specially explore new method reveal research domain importantly.The paper work is carries on under the self-consistent field theory frame. We utilize grid self-consistent field method study on the physically associating polymer solution. Paper contents divide into two parts: First, we utilize self-consistent field equation research polymer solution phase separation. Second, in the foundation which separation, we introduces gel transition judge law, Namely, utilize stress change suddenly judge rich polymer gel transition.One,study phase separation .First we structure polymer single chain partition function, obtain system free energy through monomer potential field and polymer volume fraction conjugate relation, finally through iteration solution. When two state free energy change satisfy certain precision, we resume system finally evolve equilibrium state.We are through polymer mutual parameter and volume fraction relation instead. As a result of polymer mutual parameter inverse the temperature, therefore along with the polymer volume fraction increase, phase curve first reduce then elevate, under hollow. Moreover, our system solvent and the polymer mixture, is the polymerization degree asymmetrical situation, the phase diagram is not symmetric, the critical point deviation polymer volume fraction small direction. We obtain the result with theory result which has been consistent. Moreover we further studied polymer sticker monomer gap, the solvent size have differently influence for polymer solution phase separation. The findings indicated, when polymer sticker monomer gap increase, phase separates mutual parameterχN increases, the increase scope quite is big, nearly changes the same scope with monomer gap; When polymer sticker monomer gap reduces, phase separation mutual parameterχNreducing which needs, also reduces scope quite is small. When solvent size reduced, phase separation mutual parameterχNincreasing, this is because solvent size reduce, unit volume dissolution polymer monomer ability enhancement, polymer monomer and solvent compatible enhancement. We study the result which obtains to polymer scientific experiment research and actual production have certain instruction significance.Two, gel transition. Polymer solution separates two phase, one phase is rich polymer, another phase is poor polymer. We withdraw polymer rich phase, exerts to it simply shear causes it to have deformation, this time system is in the non-equilibrium state, corresponding states free energy. the difference free energy of two state and the shape variable ratio is equal to the stress. Then we increase mutual parameterχN , through the stress variation judge the rich phase polymer gel phase transition. We obtained a series of results through the compute; First obtained rich phase polymer sol-gel transition, finally indicated which along with volume fraction increase, mutual parameter reduce. Next change polymer chain monomer number, finally discovered increase monomer number causes gel marginal value to change slightly, in other words, the monomer number increase can promote gel transition.Phase separation and gel transition study through polymer, we obtained quite good result, with the theory result which has been consistent, For this method compute simple, therefore it has specially advantage in application.