| Layer-by-layer assembly is a powerful method for fabricating functional multilayer thin films.It is widely used in the fields of construction of stimuli-responsive surfaces,surface modification and self-healing coatings,benifiting from its simplicity,designability and universality.Nowdays,different driving forces and new building blocks are employed for the multilayer formation,which endows the multilayer thin films with new structures and functions.By using unconventional layer-by-layer assembly,nanothin films with predesigned structures and versatile functions can be realized by incorporating a wide range of building blocks into the LbL films.In this dissertation,by combining layer-by-layer assembly and host-guest chemistry,a series of stimuli-responsive functional surfaces,including interfacial polymeric networks with photocatalytic property,and multilayer thin films with molecular recognition property,are fabricated,respectively.Driven by host-stablized π-π interactions,interfacial polymeric netwoks have been obtained by alternating deposition of porphyrins with four naphthene groups(TPOR)and CB[8].The polymer networks are extremely stable because of the high binding constant as well as the multiple interactions between TPOR and CB[8].Under white light irridation,the generated singlet oxygen from porphyrin groups can oxidize different kinds of phenols,which endows the multilayer films with photocatatic property.By transferring supramolecular polymercization from solutions onto surfaces,interfacial functional supramolecular networks have been obtained with conmbination of layer-by-layer assembly and supramolecular polymerization.Side-chain azobenzene containing polyelectrolyte has been designed and synthesized.And after binding with CB[8],the supramolecular complex was employed as building blocks for layer-by-layer assembly to fabricate CB[8]-containg multilayer films.Since CB[8] can hold an electron doner and an electron acceptor together in its cavity to form charge transfer complex,methyl viologen can be incorporated into the multilayer films.Moreover,owing to the photo isomerization of azobenzenes group,methyl viologen can be released from the multilayer films by UV irriadation.As a result,by combining photo-chemistry with interfacial supramolecular self-assembly,photo controlled reversible uptake and release of cargo molecules can be achieved.WP6-containing multilayer films have been obtained by alternatively deposition of water-soluble WP6 and photoreactive polyelectrolyte DAR.After photo-induced crosslinking,the as-prepared films have showed selective adsorption for guests with methyl viologen moiety.Morever,by changing pH or polarity of the solvent,the electrostatic interaction between WP6 and methyl viologen can be destroyed,leading to the release of guests.To sumarise,by transferring recognition property of WP6 from solutions onto surfaces,pH/solvent dual responsive guest recognition can be achieved with the WP6-containing multilayer films. |
