Preparation And Application Of Fluorine-containing Photo-responsive Materials

As a spontaneous phenomenon,the wrinkling phenomenon is widespread in nature.It can create unique and complex topography on the surface of the material and achieve the preparation of surface wrinkles with different scales.With this property,studying how to eliminate wrinkles having a reverse effect or create wrinkling patterns with a specific morphology is important.At present,in order to obtain controllable micro-nano patterns,dynamic responsive materials has been introduced in the surface wrinkling to expand its applications in the fields of information storage,optical devices,biosensors and so on.In this thesis,we incorporate the photo-responsive material that fast response,high reversibility and without contact into surface film to dynamically tune the surface wrinkles morphology based on the surface wrinkle mechanism.In the paper,from the perspective of polymer synthesis design,we combine the characteristics of fluorine-containing photo-responsive materials with the surface wrinkling technology to design and synthesize several azobenzene polymers with novel structures for building an intelligent responsive wrinkle system.The optical properties of polymer film materials and their ability to construct the pattern were investigated.The research contents were descripted as the following:?1?An epoxy oligomer PAFAB with an azophenyl group at the side chain was synthesized by ring-opening polymerization reaction of bisphenol AF diglycidyl ether?BADFGE?and p-aminoazobenzene?AAB?.PAFAB was characterized by FTIR,¹H NMR,¹⁹F NMR and gel permeation chromatography?GPC?to confirm the successful synthesis of side chain oligomers.Then,the epoxy oligomer film was attached to an elastic substrate?polydimethylsiloxane,PDMS?by spin coating,and the surface wrinkles was formed by a heating/cooling cycle.The photo-softening of the film and photoisomerization capabilities of the azobenzene structure due to visible light irradiation release stress in the film/substrate system and dynamically control the surface wrinkle morphology.The ability of polymer to prepare advanced wrinkle morphology was investigated.The results show that the time required for the oligomer film system to create advanced wrinkle patterns was shorter than that of homologous stilbene compounds or aminoazobenzene-containing polymers.The wrinkles in the exposed region could be erased in tens of seconds and the wrinkles in the non-exposed area still existed by selective exposure.Therefore,we can obtain Information patterns with different morphologies.The high-resolution wrinkle pattern could be rewritten in multiple cycles,indicating its great potential for rewritable information storage.?2?A series of polymers with azophenyl groups at the main chain were synthesized and their ability to form and eliminate wrinkles in the film/substrate systems was explored.Firstly,the main-chain azobenzene polyamic acid?PAA?was successfully synthesized through one-step linear polycondensation of hexafluorodianhydride?6FDA?and p-diaminoazobenzene?ADA?and spin-coated on the PDMS to construct a film/substrate system.The surface can still form a labyrinth-like wrinkle morphology after heating.Under visible light irradiation,wrinkle could be eliminated and the conditions that it happened were more difficult.The prepared wrinkle pattern had longer storage time than the side-chain azobenzene polymer.Wrinkle patterns can also be formed by selective exposure with different copper meshes.Although the orientation of the boundary region was not very good.This showed that the main-chain azobenzene polymer was stable and can't be disturbed by the boundary effect.In addition,an epoxy-based main-chain azobenzene polymer were polymerized by bisphenol A diglycidyl ether and 4,4'-dihydroxy azobenzene and were also used as a surface film material.Although the wrinkles amplitude were ununiform,complete surface wrinkles can also be obtained.And the wrinkles can also be eliminated due to the photoisomerization of azophenyl groups.Finally,isophorone diisocyanate was reacted with 4,4'-dihydroxy azobenzene to obtain an isocyanate-based polymer.Due to the presence of cycloalkanes,the entire polymer chain could not form a continuous conjugated structure.Therefore,it's rigidity was large and the area that wrinkles can be formed was small.But the formed wrinkle can also be erased under the visible light irradiation.The results indicate the feasibility that main-chain azobenzene polymers for dynamic responsive system and optimize the approach that surface wrinkling were applied in the fields of preparing advanced patterns and persistent information storage.