Self Assembly Of Nanoparticle Based On Host-guest Interaction

To obtain hierarchical structure of supramolecule system throughhost-guest chemistry is frequently under spotlight of scientific research. Inthis dissertation, we synthesized a functionalized POSS with eight pendentβ-CD groups, referred to as POSS-（CD）₈,as a host and a series of differentmolecular weight PEGs functionalized with adamantane groups at bothends （Ada-PEG-Ada）, or PEG with an adamantane at one end andazobenzene group at another （Ada-PEG-Azo） as guests. Theself-assembling system was further formed by mixing POSS-（CD）₈andfunctionalized PEG guests through host-guest interaction.The POSS-（CD）₈host was synthesized through hydrosilationreaction between mono-6-vinyl-β-CD and POSS-SiH. Ada-PEG-Adaguests with three different molecular weights （Mn=600,2100,5000g/mol）were obtained by attaching adamantine groups at the ends of PEG.Hetero-telechelic PEG （Mn=3000g/mol） Ada-PEG-Azo was prepared byutilizing thiol-ene click chemistry. The complex constant （Ka） ofadamantine and β-CD in DMSO was estimated to be approximately10M-1by NMR titration experiment. The self-assembly was carried out in the DMF/H2O （1:1） and DMSO/H2O （1:1） solutions using Ada-PEG-Ada（5000）/POSS-（CD）₈and Ada-PEG-Azo （3000）/POSS-（CD）₈, respectively.It was observed that the viscosities of these two self-assembling systemsare different. This is due to the difference of complex interactionsbetween adamantine/β-CD and azobenzene group/β-CD. Investigation onstructure and mechanical properties of this type of system, including thecontrol of sol-gel formation via cis-trans transformation of azo group isunderway.