Mechanical Properties And Destabilization Of Soft Matter

Soft matter are closely related to people's daily lives,and they have extremely wide applications in human production and technology.In today's science,soft matter has become a new frontier discipline in the discipline of physics.Controlling the morphologies and properties of the surface or interface of soft matter provides new opportunities in many engineering applications.Crease is a widely observed deformation mode in nature and engineering applications for soft polymers where the smooth surface folds into a region of self-contact with a sharp tip,usually induced by the instability from mechanical compression or swelling.The work of this paper mainly focuses on two parts.In the first part,we study the formation of surface/interface crease under biomaterials hydrogel swelling instability.In the second part,we study the surface instability on bilayer hydrogels under compression or expansion.In the first part of work,we explore the competition mechanisms between surface and interface creases through numerical simulations and experimental studies on bilayer hydrogels.Through extensive numerical simulations,we find that the surface or interface crease of the bilayer hydrogels under swelling is governed by both the modulus ratio and the height ratio.The interface crease of the bilayer hydrogels can only occur at a moderate modulus ratio and a large height ratio.Finally,we verified our numerical simulation results through experiments.In the second part of work,We combined with the linear theory,the finite element simulation and experiment to study the surface instability on bilayer hydrogels.Through the study we find that the thickness of the upper film in the bilayer structure can affect the appearance of surface instability.We also find that applying pre-expansion to the upper layer also has an effect on the surface morphology and critical instability strain after destabilization.Finally,we conclude the results to obtain a phase diagram that can predict the appearance of instability under different conditions.