Research On Additive Manufacturing Of Pdms Based On Macroscopic Supramolecular Assembly

Polydimethylsiloxane(PDMS)is an elastomer with excellent characteristics such as high flexibility,optical transparency,biocompatibility,and high oxygen permeability,and is widely used in microfluidic chips,flexible devices,biological materials,etc.In recent years,people have been striving to prepare complex PDMS structures quickly and efficiently through additive manufacturing technology.However,due to the lower viscosity and slower curing speed,PDMS is difficult in applying to traditional 3D printing equipment.There are certain challenges in achieving additive manufacturing of PDMS elastomers.Macroscopic supramolecular assembly(MSA)is a process of constructing bulk supramolecular materials by using the non-covalent interaction with building blocks above 10 micrometers modified with supramolecular groups,which is a bottom-up,efficient and controllable methodology,and is expected to provide a new strategy for the additive manufacturing of PDMS elastomers.However,the current research on MSA mostly focuses on hydrogel system,while the construction of non-gel assemblies requires the introduction of external force assistance or cumbersome modification process.Therefore,in view of the problem of efficiently constructing PDMS assemblies with MSA,we adjusted the intrinsic mechanical properties of PDMS by changing the content of curing agent and explored the elastic modulus and efficient construction of PDMS.The main research results are as follows:(1)With the strategy of changing the intrinsic properties of the material,we changed the content of the curing agent to obtain PDMS building blocks with continuously controllable modulus,which gradually decreased from 2.43 MPa to 0.14 MPa.(2)In large-scale assembly experiments,as the modulus of the PDMS building blocks gradually decreases,the assembly probability gradually increases,and when the modulus drops to 0.14 MPa,100%complete assembly can be achieved.In addition,the in-situ mechanical test proves that the interaction force between the building blocks also increases with the decrease of modulus.(3)Based on the dependency between PDMS modulus and assembly probability,a new method for efficiently implementing additive manufacturing of PDMS through MSA has been developed,and additive manufacturing of PDMS based on MSA can be carried out on a large scale,which greatly improves the construction efficiency of the structure.