Sharply thermo- and pH-responsive pentablock terpolymer with a core-shell-corona structure was prepared by RAFT polymerization of N-isopropylacrylamide and methacrylic acid monomers using PEG-based benzoate-type of RAFT agent. The PEG-based RAFT agent could be easily synthesized by dihydroxyl-capped PEG with 4-cyano-4-(thiobenzoyl) sulfanylpentanoic acids, using esterification reaction. This pentablock terpolymer was characterized by 1H NMR, FT-IR, and GPC. The PDI was obtained by GPC, indicating that the molecular weight distribution was narrow and the polymerization was well controlled. The thermo- and pH-responsive micellization of the pentablock terpolymer in aqueous solution was investigated using fluorescence spectroscopy technique, UV–vis transmittance, and TEM. The LCST of pentablock terpolymer increased (over 50 °C) compared to the NIPAM homopolymer (~32 °C), due to the incorporation of the hydrophilic PEG and PMA blocks in pentablock terpolymer (PNIPAM block as the core, PEG the block and the hydrophilic PMA block as the shell and the corona). Also, pH-dependent phase transition behavior shows at a pH value of about ~5.8, according to pKa of MAA. Thus, in acidic solution at room temperature, the pentablock terpolymer self-assembled to form core–shell–corona micelles, with the hydrophobic PMA block as the core, the PNIPAM block and the hydrophilic PEG block as the shell and the corona, respectively.

The goal of this study is to synthesize, characterize and investigate some physicochemical properties of conductive polyaniline-g-polystyrene/Fe 3 O 4 (Fe 3 O 4 /PSt-g-PANi) nanocomposites. For this purpose, initially, Fe 3 O 4 nanoparticles were synthesized by a co-precipitation method. Then, the desired nanocomposite was synthesized in two steps. First, the atom transfer radical polymerization (ATRP) of styrene was performed using an ATRP initiator attached to the surface of Fe 3 O 4 nanoparticles, followed by functionalization of the Fe 3 O 4-PSt with amine groups (-NH 2). Second, surface oxidative graft copolymerization of aniline was accomplished using the-NH 2 moieties on the Fe 3 O 4 /PSt-NH 2 as the anchoring sites. The prepared materials were characterized by various instruments, including TEM, SEM, TGA, EDX, FT-IR, XRD and conductivity measurements. The results indicated that the synthesized conductive polymer/Fe 3 O 4 nanocomposites had higher electrical conductivity and thermal resistance than those of the corresponding homopolymers.

A drug delivery system based on dual responsive units was developed. An appealing pH- and thermo-responsive triblock terpolymer as the drug carrier was synthesized by RAFT polymerization of N-isopropyl acrylamide and methacrylic acid monomers using PEG-RAFT agent. The FeO magnetic nanoparticles were synthesized by co-precipitation of Fe salts. Synthesized samples were characterized by FT-IR, XRD, GPC, SEM and TEM. The dual responsive behaviour and self-assembly of the triblock terpolymers in aqueous solution were investigated using UV-vis transmittance and DLS. Based on the results of DLS and TEM, the average size of micelles was 170, 125 and 30 nm. The triblock terpolymer was used as a chemotherapy drug carrier and doxorubicin as a model drug. The release rate of the drug at two different temperatures (37 °C and 42 °C) and pHs (5.8 and 7.4) was studied. The in vitro cytotoxicity assay of free doxorubicin and drug-loaded magnetic nanoparticles was studied. The MTT assay exhibited that these polymers are biocompatible and no toxicity. As well, IC of the DOX-loaded triblock terpolymer in MTT test demonstrated that these systems could be suitable for the treatment of cancer.

Well-defined polymer-TiO 2 nanocomposites of core-shell structure were prepared by two-steps, surface-initiated atom transfer radical polymerization (ATRP) of styrene and in situ chemical oxidative polymerization of aniline monomers from the surfaces of the TiO 2 nanoparticles. The methods used include the following: initially, the ATRP initiator was covalently attached to the surface of TiO 2 nanoparticles by esterification of 2-bromo-2-methyl propionic acid with hydroxyl group. The metalcatalyzed radical polymerization of styrene with modified TiO 2 nanoparticles was performed using a copper catalyst system to give the TiO 2 -based core hybrids linking PSt segments (TiO 2 -PSt hybrids). Next, the TiO 2 -PSt reacted with HNO 3 /H 2 SO 4 to produce a nitro group containing polystyrene to form TiO 2 -PSt-NO 2 , and obtained TiO 2 -PSt-NO 2 was treated with hydrochloric acid/SnCl 2 , and converted to an amine group containing polystyrene (TiO 2 -PSt-NH 2 ). Finally, surface oxidative graft copolymerization of aniline, using the -NH 2 moieties of TiO 2 /PSt-NH 2 as the anchoring sites. Characterization of these well-defined nanocomposites included FTIR, thermogravimetric analysis, transmission electron microscopy, and X-ray diffraction.

Through the present paper, a triblock copolymer containing pH-responsive (polyacrylic acid-b-polycaprolactone -b-polyacrylic acid) (PAA-b-PCL-b-PAA) was synthesized by using the ring-opening polymerization (ROP) of ε-caprolactone (ε-CL) and the reversible addition fragmentation chain transfer (RAFT) polymerization of the acrylic acid methods, as the drug carrier. Blends of the nanocrystalline zinc oxide nanoparticles (n-ZnO) and triblock copolymer treated from the solution have been used to make the hybrid polymer-metal oxide for the preparation of the drug loaded nanocomposite. The drug-release behavior of the nanocomposite was studied by using the Doxorubicin as a model drug. In addition to the self-assembly and pH-responsive behavior of the triblock copolymers/ZnO was studied in solution by the Fluorescence Spectroscopy, Scanning Electron Microscopy(SEM), Transmission Electron Microscopy (TEM), DLS, HNMR and FT-IR spectroscopy.