Multiscale Simulation Of Hyperbranched Polymerization

The kinetics and thermodynamics have great impacts on the synthesis and application of dendritic polymers.In order to investigate the kinetics of specific hyperbranched polymerization,a reactive multiscale model has been developed.Due to the complex structure of dendritic polymer,REMD simulation method has been employed to study the phase transition behavior of single homogenious dendritic chain,furthermore,the thiol-ene asysmetry polymerizaion has been studied by TDDFT method.The contents of the research work include:1.A reactive multiscale model has been developed to study the AB₂ type polymerization,the coarse-grained force filed are extracted from the atomistic system,the pre-condition for reactivce Monte Carlo is the subtituent effects of different functional groups,which are obtained through fitting experimental data.Using this model and optimized parameters,we can quantitatively predict the reaction progress,the calculated degree of polymerization,degree of branching and polydispersity index are agree with that of the experimental data.2.The reversible deactivation/activation progress has been added into the RMCCGMD model to study the polymerization reaction employing ATRP mechanism.The method for obtaining CGFF and the precondition for the multiscale model are the same with the previous work.The general properties for the catalytic ratio,the chain propagating rate constant and the ATRP equilibrium constant are agree well with the experimental results and the analytic model.Using the optimized reactive parameters,the calculated distribution of structural units and the degree of branching match with the experimental data,furthermore,the information of intramolecular ring is provided precisely.3.The influence of DB,chain stiffness and the structural regularity on the phase transition behavior of single dendritic chain are investigated by REMD method,the CG trantion is controlled by the number of linear unit,the DB and structural regularity influence the LS transition,but have no impact on the CG transition,the chain stiffness only influence the LS transition.4.The UV and CD spectra of chiral monomer and radical are calculated by TDDFT method,by comparison to experital phenomenon,we conclude the reason why the asymmetry polymerization have occurred from the reacmic monomer system under irradiation of circular polarized light.The calculated results by different functional theories are compared as well.