Monte Carlo simulation on sequence statistical structures of gradient copolymers

The simulation of controlled/living radical copolymerization (CRcP) is conducted using the method of Monte Carlo. Target Markov chains are obtained by calculating transfer probabilities instantly. The statistical results which are all the functions of conversion are obtained, including cumulative composition, segment length distribution, dyad and triad concentrations. The effect of reaction parameters on gradient structures is investigated, including initiation rates, monomer feed ratio and reactivity ratios. The results show that reactivity ratios, monomer feed ratio and conversion are more important parameters that can affect gradient structure than initiation rates. Initiation rates can cause difference in sequence structures at early stage of copolymerization and affect cumulative compositions continuously to a moderate degree. Monomer feed ratio mainly affects the fore-head of gradient copolymers while conversion simply affects the rear-end of gradient copolymers. The results of segment length distribution show that with the increase of difference in reactivity ratios, the distribution changes from Flory distribution which indicates random structure to Poisson distribution which indicates block composition.