Research On PDMS Bonding Under Plasma Method

Polydimethylsiloxane(PDMS)is a kind of high-molecular polymer.It has become one of the most popular materials in the field of stretchable electronics due to its ductility,optical properties,insulation,corrosion resistance,biocompatibility,simple production and low cost etc.But the surface of PDMS has a natural hydrophobic.PDMS can’t form irreversible bonding with homogeneous or heterogeneous things without modification treatment.This limits its application space.In this paper,we study the bonding conditions and bonding effects of PDMS with various substances by the plasma method.Firstly,we make a brief introduction about the structure,properties and fabrication process of PDMS.Then we test the elastic modulus of PDMS with various ratios(prepolymer:curing agent).Secondly,we discuss the relationship between curing temperature and precuring time in PDMS/PDMS irreversible bonding by thermal diffusion method.Moreover,there are three main parameters of plasma method:the radio frequency power,modification time and air flow scheme.According to bonded area percentage for evaluation standard,we design orthogonal experiment and make the irreversible bonding test of PDMS/PDMS,PDMS/glass and PDMS/silicon to explore their optimal process parameters.Finally,we design single factor experiment to explore the influence of each parameter on the bonding strength.The main conclusions are as follows:1.The preparation process of PDMS,the process of thermal diffusion mehtod,the process of plasma method for PDMS and points for attention in each process were clarified.2.Research shows that when the ratio of PDMS increases,the elastic modulus of PDMS matrix gradually decreases.The data is fit to obtain the relationship between the elastic modulus of PDMS matrix and the ratio with high accuracy.Thermal diffusion method can achieve the irreversible bonding of PDMS/PDMS.With the increasing of the curing temperature of PDMS,the precuring time decreases.3.In the current experimental environment and experimental conditions,when the radio of PDMS is 5:1,it couldn’t achieve irreversible bonding with homogeneity and heterogeneity.When the radio of PDMS is 5:1.the optimum process parameters of PDMS/PDMS and PDMS/silicon are:400W,2.5L/min,2min;400w,2.5 L/min.2min.Their percentage of bonding area increases with the increaseing of bonding time and bonding loading pressure.But both of them have a critical point.On the premise of the bonding area percentage meeting the experimental requirements,the bonding time of PDMS/PDMS is 5min,PDMS/glass is 5h,and PDMS/silicon is 12h.4.In the single factor experiment,we study the influence of three parameters on the bonding strength of PDMS/PDMS,PDMS/glass,PDMS/silicon by plasma method.Studies have shown that the increase of rf power can promote the bond strength of all three.The other parameters have different effects under different bonding substances.The work of this paper is a preliminary exploration to the group.Under the existing experimental conditions,it is the first systematic and comprehensive study on the irreversible bonding of PDMS/PDMS,PDMS/glass and PDMS/silicon by plasma method.We explore the bonding processes and the effect of parameters and the bonding effect.We put forward the optimum process parameter of the irreversible bonding of PDMS with homogeneous or heterogeneous things.It provide the support of data and the guidance of process for the next research of the group.