Preparation And Characterization Of Thermo-sensitive Organic-Inorganic Hybrid Nanocapsules

The thermo-sensitive organic-inorganic hybrid nanocapsules not only have excellent thermal properties, mechanical properties and solvent resistance of organic-inorganic materials, but also they have fast response behavior on the temperature. Therefore, the temperature-sensitive organic-inorganic hybrid nanocapsules have great application prospects in biomedicine fields, especially in controlled release of the drug. In this paper, A thermo-sensitive organic-inorganic nanocapsules were synthesized by miniemulsion polymerization through comonomer N-isopropylacrylamide(NIPAM) was introduced in the copolymerization of styrene(St) and y-methacryloxypropyl trimethoxy silane(KH-570). The preparation conditions of organic-inorganic hybrid nanocapsules and the influence of amounts of NIPAM on the morphology and controlled release properties of nanocapsules were studied. The main contents of this paper are as follows:1. The properties of microcapsules, preparation method and application of organic-inorganic hybrid materials were reviewd.The phase transition mechanism and application of NIPAM were introduced.2. A organic-inorganic nanocapsules were synthesized by miniemulsion polymerization using octane as template, styrene(St), and γ-methacryloxypropyl trimethoxy silane (KH-570) as monomers, and sodium dodecyl sulfate (SDS) as the emulsifier, divinylbenzene(DVB) as a crosslinking agent, hexadecane(HD) as co-stabilizers.The influence of amounts of crosslinker, monomer and pH on nanocapsules formation were studied. The results showed that a larger number of better morphology nanocapsules were formed when pH=7, the amount of DVB, St and KH-570were0.4g,3.33g and,l.Og, respectively.3. A thermo-sensitive organic-inorganic nanocapsules were synthesized by miniemulsion polymerization using octane as template through introducing the comonomer N-isopropylacrylamide(NIPAM) to the copolymerization of styrene(St) and y-methacryloxypropyl trimethoxy silane(KH-570). The influence of amounts NIPAM on the structure, morphology and the penetrative properties of nanocapsules were studied.The results showed that complete morphology, uniform and monodisperse nanocapsules were obtained when the amount of NIPAM was0.4g. The average diameter and shell thickness of nanocapsules were167nm and24nm respectively.The penetrative properties of nanocapsules enhanced obviously with the increase of the amount of NIPAM. The LCST of nanocapsules was between50℃-60℃.4. The poly(St-co-BA) thermo-sensitive organic-inorganic nanocapsules were synthesized by miniemulsion polymerization through introducing monomer BA to the copolymerization of styrene(St) and y-methacryloxypropyl trimethoxy silane (KH-570). Effects of the type initiator and the St/BA ratio on particle size, morphology and LCST of nanocapsules were investigated. The results showed that better morphology nanocapsules could be obtained when St/BA mass ratio is2/2and AIBN is0.3g.The LCST of nanocapsules is decreased by adding the monomer BA.