Fabrication Of Surfae Silvered Polyimide Films Via In-situ Selective Ion Exchange Technique

In this dissertation,we report our efforts on the preparation of surface silvered patterning polyimide films with excellent reflectivity and interfaces adhension via in-situ selective ion exchange technique using BPDA/ODA or BTDA/ODA as the matrix.We have established the relationships of surface properties with the surface morphology and the surface composition of the composite films,and the best prepared route was selected.In this dissertation,we used BPDA/ODA-based polyamic acid as the matrix.In the process of ion exchange,when silver nitrate is used as the silver source to prepare the silver paint treated polyamic acid film,the polyamic acid induces macromolecular cross-linking under the induction of silver ions.And it can not be dissolved in its good solvent.When the percentage of silver nitrate in silver paint is 33.3%,the ion exchange time is 1 h,and the ambient temperature is 30?,the silvered polyimide film has better performance.When silver ammonia solution was used as the silver source to prepare the alkaline silver paint,the volume fraction of silver ammonia was 5%,and the silver ion loading on the surface of the film was saturated when the ion exchange time was 30 minutes.At the same time,the experiment also found that adding an appropriate amount of wetting agent in the silver paint can reduce the contact angle between the substrate and the silver paste,so that the silver paint can spread more thoroughly on the surface of the film,thereby improving the efficiency of silver ion exchange of hydrogen ions per time.In chemical reduction process,with 0.15 M DMAB reduction 30 min,thermal treatment 300 ? for 6 h,the preparation of the composite membrane surface reflectance was 84.874%,and the resistance was 28 ?/sq,the mechanical strength was 149.8 MPa.We compared the differences in the morphology of the silver layer of silvered polyimide films in different systems.It was found that PMDA/ODA-based silvered polyimide films were degraded under the same experimental conditions.BPDA/ODA and BTDA/ODA-based silvered polyimide films had better silver surface morphology and compact silver particles.while the silver particles on the surface of the ODPA/ODA-based silvered polyimide films are island-inlaid.The experiment uses BTDA/ODA-based polyamic acid as the matrix.During the ion exchange process,we used the silver paint prepared by silver nitrate with a percentage of up to 20.0%as the silver source to treat the polyamic acid film for 30 min.When the 0.1 M DMAB was reduced for 40 min and the thermal treatment was performed at 300? for 2 h,the surface reflectivity of the composite films reached 82.571%,the electrical resistance was 35 ?/sq,the thermal stability and interfacial adhesion were excellent,and the mechanical strength was 121.2 MPa.