Studies On The Surface Modification Of Polymeric Vesicles And Supramolecular Hydrogels Based On The Inclusion Complexation Interactions

During the last 20 years,our research group has suggested and developed a new concept of"Non-Covalent Connected Micelles"(NCCMs).Recently,we constructed a new kind of NCCMs using the host-guest recognition interactions as the driving force for the macromolecular self-assembly.Based on the previous research works in our research group,the present research works mainly focus on the surface modification of polymeric vesicles and self-assembly organic-inorganic hybrid supramolecular hydrogels using the inclusion complexation interactions between cyclodextrin(CD) and guest molecules as the driving force.The projects of this thesis are as follows:1.Surface modification of polymeric vesicles based on inclusion complexationA novel kind of vesicle,which is reactive in supramolecular chemistry, was prepared throughβ-CD-ended polyetherimide in water.On both the outer and inner surfaces of the vesicles,β-CD cavities are available for further surface modification via inclusion complexation betweenβ-CD and adamantane-monoended PEG with different molecular weights.This study opens a new,simple,mild avenue to the surface modification and functionalization of the vesicles,which of course would promote their applications in various areas.2.Low molecular weight PEG/α-CD based native and SiO₂ nanoparticle hybrid supramolecular hydrogelsAs quite generally stated in the literatures,low-molecular-weight(MW) poly(ethylene glycol)(PEG)(Mn less than 2K) andα-cyclodextrin(α-CD) can lead to only crystalline precipitates(not hydrogels).However,in this study we found that:(1) adamantane monoend-functionalized low-MW PEG(Ada-PEG, Mn=1.1 or 2K) andα-CD lead to hydrogels but not to crystalline precipitates and(2)β-cyclodextrin(β-CD) surface-functionalized silica nanoparticles (β-CD-SiO₂) can be well dispersed in low-MW Ada-PEG andα-CD aqueous mixtures,resulting in hybrid hydrogels.The hydrophobic aggregation of Ada-PEG in case 1 and the further functionalization ofβ-CD-SiO₂ with PEG chains due to the inclusion complexation betweenβ-CD and the Ada group attached to PEG in case 2 were found to play a key role as a supra-cross-linker (SCL) that promoted the gelation of the inclusion complexes ofα-CD and the low-MW Ada-PEG. 3.Hybrid supramolecular hydrogels using CdS quantum dots as supra-cross-linkers via host-guest interactionBased on the above said SCL concept,a novel versatile and simple method of preparing QD hybrid supramolecular hydrogels usingβ-CD capped QDs as a Supra-Cross-Linker(SCL) via host-guest interaction was proposed in this part,. The QDs were stably fixed in the hydrogels by inclusion complexation rather than chemical bonding.Using this method,new nanostructured hybrid hydrogels can be prepared by copolymerization of the SCLs with water soluble monomers.The present hybrid hydrogels are transparent and homogenous, which benefits their applications in optical devices and biomaterials.4.CdS quantum dots hybrid water soluble supramolecular polymer network based on inclusion complexationIn this part,a novel kind of water soluble organic-inorganic hybrid 3D supramolecular polymer network was constructed using the inclusion complexation interaction betweenβ-CD and adamantane andβ-CD capped CdS quantum dots as the driving force and supra-cross-linker,respectively. The hybrid network structure was characterized by TEM and AFM.The fluorescent experiments showed that the formation of the network structure did not destroy the surface structure of the quantum dots,and can improve the fluorescent strength of the quantum dots.