Monte Carlo Simulation On The Self-healing Of Dynamic Bond-based Gel

Gels have become especially attractive in the biological field due to their possible applications as soft artificial tissues.However,these materials are susceptible to mechanical,chemical,and thermal damage or a combination of these factors,which could lead to the formation of microcracks deep within the structure.It is difficult or even impossible to detect and repair the microcracks by external intervention.The presence of the microcracks in the polymer matrix can affect both the fiber-and matrix-dominated properties of a composite.The development and characterization of self-healing synthetic polymeric materials based on reversible non-covalent and covalent bonds have been inspired by biological systems in which damage triggers an autonomic healing response.Lattice-gas model is proposed to describe self-healing process occurring on the crosssections of a dynamic bond-based gel.The equivalence between lattice-gas and Ising models makes the self-healing process be identified as a first-order thermodynamic phase transition.This is confirmed by the specific heat obtained by the Monte Carlo simulation on the selfhealing,by which the critical association fraction is also determined.Furthermore,the significant effects of association strength of the dynamic bond,cooperation effect,and distance between cross-sections on the self-healing process are found,where the associating strength plays an important role.It is expected that the present result is helpful to the material design of self-hearable gel.There are three chapters in the dissertation as following:Chapter 1: An introduction to the background and significance of self-healing gels based on reversible bond,which includes the characteristics of self-healing gels,self-healing mechanisms and relative models used to study this process.Furthermore,the factors of the selfhealing in the experiments are summarized.In the end,Ising model and lattice-gas model are introduced and compared.Chapter 2: The significant effects of association strength of the dynamic bond,cooperation effect,and distance between cross-sections on the self-healing process are found,where the associating strength plays an important role.It is expected that the present result is helpful to the material design of self-hearable gel.Chapter 3: The relationship between the association fraction and Monte Carlo steps(MCS)is presented.The cooperation effect leads to the decreasing of the distance between crosssections.As a result,the dynamic processes are simulated that the association fraction increases with decreasing of the distance under different conditions.Furthermore,the effects of association strength of the dynamic bond,cooperation effect,and distance between crosssections on the efficiency of the self-healing process are mainly discussed.Chapter 4: The results of self-healing gels based on reversible bonds are concluded and the deficiencies for the present study are also pointed out.Furthermore,the potential applications of the present research are outlined.It is expected that the investigation of selfhealing gels based on reversible bonds could draw more attention in the field of experiments.