Study On Synthesis, Characterization And Properties Of Amphiphilic Polymers Containing Methacrylate

Amphiphilic polymers have received considerable attention due to their ability to self-assemble in bulk and in solution forming a range of different morphologies (e.g., spheres, rods, lamellae and large compound vesicles) through weak noncovalent interactions. These resultant aggregates have very interesting particular properties, so they have many potential applications in areas such as microreactors, microcapsules, drug delivery systems and encapsulation of various kinds of guest molecules. In this paper, progress in synthesis, self-assembly and application of amphiphilic polymers were reviewed. Many amphiphilic polymers containing mathacrylate were prepared and characterized. The self-assembly behavior of the resultant polymers in mixed solvents was investigated.Maleic anhydride-stearyl methacrylate (MA-SMA) random copolymer was synthesized via the free radical polymerization and its amide was prepared through the MA moieties being reacted with morpholine. The resultant polymers were characterized by ¹H-NMR, FT-IR and GPC It was found that the resultant polymers could form various morphologies in THF/H2O by adjusting the concentration and water content. The hydrolyzate of P(SMA-co-MA) can self-assemble into large compound micelles (LCMs) with diameter of ca. 300nm at water content of 5.32wt%, while it can form vesicles at water content of 18.35wt%; P(SMA-co-MPMA) can yield pearl-necklace aggregates at the concentration of 0.11wt% in THF/H₂O 88.9/11.1 (WAV). The effect of the polymer-solvent interaction on these aggregations was discussed. P(MA-alt-SMA)-b-PSMA having alternating segments was prepared via the reversible-addition-fragmentation-transfer (RAFT) polymerization. The resultant polymers were characterized by ¹H-NMR, FT-IR and GPC. Various morphologies self-assembled from the hydrolyzate of P(MA-alt-SMA)-b-PSMA in THF/H₂O were obtained by varying the concentration, water content and pH value. The hydrolyzate of P(SMA-alt-MA)₅₀-b-PSMA₃₀ can self-assemble into spheres with diameter of 150～200nm at the concentration of 0.05wt%, while it can form LCMs with diameter of 400nm at the concentration of 0.20wt%.Stearyl methacrylate-N-isopropylacrylamide (SMA-NIPAAm) diblock and triblock copolymerswere synthesized via the RAFT polymerization. The resultant polymers were characterized by¹H-NMR, FT-IR and GPC. Various morphologies self-assembled from block copolymers in mixedsolvents were obtained by varying solvent, block ratio, temperature and so on. When theconcentration was maintained at 0.10wt% in THF/H₂O 70/30 (WAV), PSMA₂₉-b-PNIPAAm₂₃ canself-assemble to giant compound vesicles with diameter of 30μm, PSMA₁₇-b-PNIPAAm₄₀ can form giant vesicles with diameter of 5-10μm, while PSMA₁₇-b-PNIPAAm₃₂ can yield spheres with diameter of 800nm. At the same condition, PSMA₁₀-b-PNIPAAm₃₈-PSMAio can form "core-shell" spheres with diameter of 1.0μm and PSMA₁₀-b-PNIPAAm₂₆-PSMA₁₀ can yield vesicles with diameter of 250nm.t-Butyl methacrylate-N-isopropylacrylamide (tBMA-NIPAAm) diblock copolymer was synthesized via the RAFT polymerization and (P(MAA-co-PyMA)-b-PNIPAAm) was prepared through the hydrolysis and esterification reactions. The resultant polymers were characterized by ¹H-NMR, FT-IR and GPC. Their self-assembly behaviors were studied in different solvents. It was found that spheres, vesicles and network can be obtained through the self-assembly of PtBMA-b-PNIPA Am/THF/H₂O system; vesicles and cross-linked network can be formed through the self-assembly of PtBMA-b-PNIPAArn/1,4-dioxane/H₂O system. The self-assemble behavior of P(MAA-co-PyMA)-b-PNIPAAm in 1,4-dioxane/H₂O was also investigated. Stable thermo-responsive fluorescent nanoballs can be prepared via the covalent cross-linking of MAA segments within the aggregates. The thermo-responsive and fluorescent properties of the nanoballs were investigated.Stearyl methacrylate-3-(trimethoxysilyl)propyl methacrylate (SMA-TMSPMA) diblock, multi-block and star block copolymers were synthesized via atom transfer radical polymerization (ATRP). The resultant polymers were characterized by ¹H-NMR and GPC. By controlling concentration, copolymer composition and solvent composition, the different aggregates could be obtained, including spheres, vesicles, LCMs and large compound vesicles. With a base catalyst, the resultant copolymers containing R-Si(OCH₃)₃ groups were subsequently transferred into the crosslinked polysilsesquioxane by the hydrolysis and condensation reactions. This sol-gel process resulted in the formation of organic/inorganic hybrid nanomaterials. Furthermore, the aggregates of PSMA₂₅-b-PTMSPMA₃ were used to encapsulate Ag nanoparticles, stable "core-shell" inorganic/polymer nanoparticles can be prepared by the sol-gel procedure.PSMA-Crown-PSMA was synthesized via ATRP. The resultant polymers were characterized by ¹H-NMR, FT-IR and GPC. By adjusting molecular weight, water content and concentration, various morphologies could be obtained, including spheres, LCMs and hollow spheres. A metal particle array based on the self-assembled template from the polymer was prepared by the galvanic displacement reaction.