Polvdopamine:from Deposition Process To Surface Functionalization

Mussel-inspired chemistry,especially polydopamine(PDA)deposition,has been as an emerging modification technology for injecting new vitality into surface science,which has widely been applied numerous frontier fields such as biology,energy and environment science.However,up to date,several scientific and technical issues remain unaddressed during conventional PDA deposition,including long deposition time,as-formed coating with poor uniformity and stability,elusive adhesion and deposition mechanism and monotonous applications design.In this thesis,we developed the rapid deposition strategy of PDA to address some above issues,and further revealed adhesion and deposition mechanism of PDA by atomic force spectroscopy(AFM)and surface force apparatus(SFA)techniques.The as-prepared PDA coatings with unique characters have been used to design and exploit various featured functional surfaces.Firstly,we developed CuSO4/H2O2-triggered rapid deposition of PDA,and the deposition rate reaches up to 45 ± 2 nm/h,which shows the fastest deposition rate reported to date.Compared with the conventional PDA deposition,CuSO4/H2O2-triggered PDA coatings exhibit high uniformity and enhanced stability in acidic and alkaline media,as well as in polar organic solvents.Secondly,we developed a colloidal probe AFM technique to quantify the interaction forces and adhesion between the PDA coatings and the substrate surfaces with different wettabilities.The surface force measurements and thermodynamic analysis of interaction energy have clearly elucidated the deposition mechanism of PDA on the substrate surfaces of varying hydrophobicity.Besides,SFA technique was used to in situ characterize the adhesion of PDA coatings and its derivatives(polycatechol,polyDOPA,polyepinephrine and polynorepinephrine).In combination with the difference of as-measured adhesion and the result of electron densities and adsorption energies calculated by density functional theory(DFT),the origin of the strong attraction between PDA coatings is probably due to cation-?interactions attributed to primary amine and indole motifs of molecular structure.Thirdly,various functional surfaces can be fabricated by combining with the properties of CuSO4/H2O2-triggered PDA coatings and substrates with different structures.The rapid deposition method can not only be used to prepare PDA coatings on silica surface with high refractive index and unifonnity for large-scale and angle-independent structural colors,but also fabricate nanoporous PDA film on PAN ultrafiltration membrane as selective separation skin of aqueous and solvent nanofiltration membrane with good performance.For polypropylene microporous membranes,PDA coatings can endow them with excellent hydrophilicity and antibacterial performance.In addition,PDA coatings were acted as the intermediate layer for in situ mineralizing ?-FeOOH on the polypropylene nonwoven surfaces.The mineralized membranes exhibit enhanced photocatalytic performance and can be assembled into photocatalytic membrane reactor for wastewater treatment.Furthermore,PDA coatings with the photothermal conversion effect are able bestow melamine sponges with solar-driven self-heating function for oil spill remediation.The self-heating sponges have high adsorption capability because of crude oil with reduced viscosity and enhanced fluidity,and are also able to be designed into a "self-heating vacuum cleaner" to realize high-efficiently continuous clean-up and collection of crude oils from the water surface.