Study On The Chemical Design,synthesis And Functions Of Polymeric Interface Materials With Wetting,adhesion And Lubrication

Inspired by the typical surfaces with wetting,adhesion,and lubrication in nature and their mechanisms,this thesis aims to develop high-performance surface/interface functional materials with wetting,adhesion,and lubrication through the synthetic chemistry of organic polymers,and to reveal the influence of molecular or network structure design,mechanical properties and chemical components on the performance of materials with wetting,adhesion,and lubrication.Taking biomimetic lubrication and interfacial adhesion as the topic of this thesis,a series of special functional interface materials with wetting,adhesion,and lubrication were constructed through interfacial design and macroscopic performance regulation.The main research contents and conclusions are as follows:1.Construction of monolayer hydrogel lubricating coating on the surface of silicone elastic substrates.Using high-purity iron powder as chemical catalyst sites,a controlled thickness layer of poly（acrylamide-co-acrylic acid）hydrogel lubricant coating was firmly grown on the surface of hydrophobic polydimethylsiloxane（PDMS）elastomeric substrates through surface catalytically initiated radical polymerization method combined with the interfacial chemical coupling strategy.The iron powder provided the Fe²⁺catalyst during the oxidation and decomposition,achieving rapid gelation of the monomer at the solid-liquid contact interface without polymerization of the bulk solution.The hydrogel coating was covalently anchored to the substrate by the silane coupling agent KH570,which is strongly bonded to the PDMS substrate.Using silicone rubber balls as sliding counter pairs and water as lubricant,the tribological properties of the hydrogel coating were evaluated.The results show that the hydrogel coating has excellent lubricating properties and good anti-wear function.This modification method is not only applicable to PDMS substrates,but also can be extended to other hydrophobic materials,providing a new idea for the modification of engineering material surfaces with water lubrication.2.Constructing bilayer bionic tough hydrogel lubricant coating on the surface of silicone elastomeric substrate.Inspired by the biphasic structure of articular cartilage,based on building monolayer high strength hydrogel coating on the surface of PDMS elastomer substrate,a bionic bilayer tough high-strength hydrogel lubricant coating was prepared to successfully achieve the unity of high load-bearing and low friction by using subsurface initiated atom transfer radical polymerization method to graft a micron-level thickness of polyelectrolyte brush layer on the surface of the tough hydrogel coating.The ATRP initiator HEMA-Br was introduced into the polymer network of the high-strength hydrogel.The ATRP reaction started to initiate polymerization from the subsurface of the hydrogel by diffusion and contacted with the HEMA-Br on the subsurface of the swelling hydrogel.The PSBMA polyelectrolyte chains were grown stereospecifically.Among them,the polyelectrolyte chain and the surface layer of tough hydrogel formed a surface composite layer.With the steel balls as the sliding counter pair and water as lubricant,the bionic bilayer hydrogel coating exhibits a low coefficient of friction（<0.05）under the contact stress of MPa and maintains a low and stable coefficient of friction and minimal wear after 50,000 cycles of reciprocal friction.This research provides a new idea for the preparation of bionic high-performance water-lubricated functional coating materials.3.Modified macromolecular lubricants with interfacial wet adhesion characteristics.Aiming at the technical difficulties such as poor lubrication performance of silicone materials and poor wettability of traditional water-based lubricants on silicone materials,a macromolecular lubricant（CS-g-PEG-g-CT）with the side chain of chitosan grafted polyethylene glycol and catechol groups was synthesized by molecular design.Fluorescent labeling and QCM experiments showed that CS-g-PEG-g-CT can produce good adsorption on the surface of silicone substrates and rapidly change their surface wettability.Tribological tests showed that CS-g-PEG-g-CT can form an effective boundary lubrication film on PDMS substrates,which shows excellent friction reduction performance.In comparison with a series of commercial contact lens lubricants aiming at silicone-based,CS-g-PEG-g-CT performs a more excellent lubrication effect.In addition,CS-g-PEG-g-CT also shows a stable and excellent lubrication effect on the surface of interventional silicone-based medical catheters,indicating the potential application of this material in the medical device field.4.Modified macromolecular materials with wet tissue adhesion and hemostatic properties.In recent years,functional wet adhesives have received extensive attention in the biomedical field.Based on the sugar-based natural macromolecule chitosan as the backbone,functional macromolecules with wet tissue adhesion and hemostatic properties CSCTK（chitosan-catechol-lysine）were synthesized by grafting adhesion fragments-catechol and lysine groups onto the chitosan backbone through two steps amidation reaction.The synthesized functional macromolecules CSCTK were configured into hydrogels,which showed excellent rheological properties,concentration-dependent gel-sol transition properties and shear thinning properties over a wide concentration range.CSCTK hydrogels were coated onto syringes and medical gauze to form functional coatings,and demonstrated good hemostatic effects in animal experiments.The resulting hemostatic needles and hemostatic dressings showed good hemostatic effects in animal experiments.Due to the excellent hemostatic properties and wet adhesion of CSCTK,this material has significant potential for application in the biomedical field.5.Synthetic copolymer adhesive materials with strong interfacial adhesion properties.Inspired by the extraordinary wet adhesion mechanism of nature mussel proteins adhesive,we proposed the polymer structure design concept of balancing cohesive strength and interfacial adhesion to prepare copolymer adhesive of[poly（dopamine methacrylamide-co-methoxethyl acrylate-coadamantane-1-carboxylic acid2-（2-methyl-acryloyloxy）-ethyl ester）][p（DMA-co-MEA-co-AD）]（SRAD）by using radical polymerization.SRAD exhibits ultra-high interfacial adhesion strength to ferrous substrates in the dry state（～7.66 MPa）and in the wet state（～2.78 MPa）.After immersing the bonded sample in water for half of a year,the interface still exhibits tough and stable adhesion strength（～2.11 MPa）.In addition,SRAD exhibits amazing wet adhesion robustness/resistance even under severe conditions such as fluid shearing,dynamic loading,and cyclic mechanical fretting.The great advantages of SRAD,such as strong interface bonding,stable wet adhesion underwater,and good mechanical tolerance,make it demonstrate a good promising application in the field of engineering sealing and underwater adhesion.