The Preparation Of Composite Nanoparticle Via Soft Nanocoupling

The study of composite nanoparticles(NPs)has been a hot area in the field of nanotechnology."Hard" coupling is one of the most popular methods up to date,which often requires harsh condition and arduous process.Therefore,we present a new method,"soft"coupling,by using coupling polymers as "binders" to bond different inorganic NPs together to form a new composite NP.In this thesis,reversible addition-fragmentation chain transfer polymerization(RAFT)is used to synthesize the coupling polymers.The process of polymerization is tracked by gel permeation chromatography(GPC)and nuclear magnetic resonance spectroscopy(NMR).The particle size is characterized by dynamic light scattering(DLS)and the morphology of the prepared composite NPs is studied by transmission electron microscopy(TEM).Raman spectroscopy is used to confirm the successful introduction of disulfide.The maj or results are as follows,1.Homo-polymer POE,di-block copolymer POE-PGMA,tri-block copolymer POE-PGMA-PMPS and POE-PGMA-P(DOPA-TBS-MAC)are successfully synthesized by RAFT polymerization.The molecular weight of polymers is characterized by GPC and the chemical structure is confirmed by NMR.The results show that PDIs of polymerization are typically lower than 1.20,indicating good control during polymerization.2.Several different types of NPs,such as gold NP,silica NP and magnetic NP are successfully synthesized according to literature procedures,and their size and morphology are characterized by DLS and TEM.From the TEM image,it is found that the size of gold NP is about 5.3 ± 1.9 nm,and the silica NP about 528±25 nm.3.Two different routes are adopted to study the soft nano-coupling between gold and silica NPs.In route 1,the triblock polymer reacts with lipoic acid at first,but the purified product is hardly soluble in THF and difficult to be applied in the next step,so a different strategy had to be applied.In route 2,firstly,the triblock polymer is reacted with silica NPs.Secondly,the polymer-coated NPs react with lipoic acid and then couple with gold NPs.It is found that the resulting SiO2-Au composite NP has a corona shell of SiO2 NPs with Au NPs tightly embedded inside,and can even tolerate harsh sonication process for 1 h.4.To prepare the composite of gold NP and magnetic NP,the reaction between dopamine-containing triblock copolymer POE-PGMA-P(DOPA-TBS-MAC)and lipoic acid is performed,and is followed by deprotection of phenolic hydroxyl groups.Some preliminary efforts on the preparation of gold and magnetic composite NP are tried,but the result is unsatisfactory and the process need be further optimized.