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A novel amphiphilic four-arm star copolymer [poly(e-caprolactone)-b-poly(poly(ethylene glycol) methyl ether methacrylate-co-p-(2-methacryloxyethoxy) benzaldehyde)]4 [4-AS-PCL-P(PEGMA-co-MAEBA)] was designed and synthesized by a combination of ring-opening polymerization (ROP) and continuous activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP). Stimuli-responsive cross-linked micelles (SCMs) were prepared by crosslinking the shell structure of the self-assembled micelles from star copolymers. The SCMs could be de-cross-linked under low pH and redox conditions. After loading with the anticancer drug camptothecin (CPT), the SCMs displayed a good stability against extensive dilution and a slow sustained drug release at pH 7.4 with 15% in 24 h, while a fast release (54%) was observed at pH 5.0 and 10 mM DTT. Confocal microscopy studies and MTT assays revealed that the CPT-loaded SCMs showed a good uptake property and a high cytotoxicity against HepG2 tumor cells. The pH/redox dual stimuli-responsive cross-linked micelles are proposed to be a highly promising platform for the intracellular delivery of insoluble chemotherapeutics for cancer therapy.

The reversible addition–fragmentation chain transfer (RAFT) dispersion polymerization of methyl methacrylate (MMA) was carried out in ethanol using polymethacrylic acid (PMAA)–4-cyanopentanoic acid dithiobenzoate (CADB) (degree of polymerization = 30, 122 and 450) as a macro chain transfer agent (CTA) and 2,2′-azobis(2,4-diemthyl valeronitrile) (V-65) as an initiator. In contrast to the random copolymerization systems, a dramatic increase of conductivity during the initial stage of RAFT polymerization was observed. It was confirmed that the conductivity resulted from the charged solvophobic blocks of soluble diblock copolymers, strongly dependent on the chain length of PMAA-CTA and PMMA. Objects of PMAA-b-PMMA were prepared by three methods, i.e. the polymerization-, temperature- and ion-induced self-assembly. The procedure of self-assembly commonly resulted in a dramatic decrease of conductivity. All results indicated that the electrostatic interaction played a role in the process of self-assembly, rather than just the solvophobic interaction of PMMA blocks in ethanol.

Employing polymethacrylic acid (PMAA) as the template and N-vinyl pyrrolidone (N-VP) as monomer, the ATRP-template miniemulsion polymerization was carried out in the aqueous medium by using MBP/CuBr/bpy as initiator. The results were characterized by dynamic light scattering (DLS), transmission electron microscope (TEM), and gel permeation chromatography (GPC). It was observed that the stable particles exhibited amphoteric pH sensitivity, namely that in the range of pH 3.0 to 5.0, the particles precipitated, whereas beyond the range the particles were stable and swollen as pH varied. Moreover, the pH range was variable according to the molecular weight of PVP. The results of GPC indicated that the molecular weight of template polymer PMAA was duplicated by the daughter polymer PVP. Being noncross-linked, unlike the common microgels, the hydrodynamic diameter dramatically increased in a very narrow pH range, e.g., pH 5.5 –6 and 2.0–2.5. Finally, the nanoparticles of PMAA/PVP were applied for the controlled release of rifampicin (RFP) and doxorubicin (DOX).

Crude polysaccharides from Costaria costata were extracted by hot water and further fractionated by anion exchange chromatography into three polysaccharide fractions. Three low molecular weight fragments were then prepared by degradation of the polysaccharides with hydrogen peroxide and ascorbic acid. The structural features of the polysaccharides and their low molecular weight fragments were elucidated for the first time based on the HGPC, FT-IR, NMR, MS, monosaccharide composition, and other chemical analyses. Their anticoagulant and FGF-1, -2, -7, -8, -9, -10/FGFR1c signaling activation activities in BaF3 cells were also examined. Our studies showed that the polysaccharides were sulfated at different positions of galactose and fucose residues. The APTT-, PT- and TT-based anticoagulant assay results indicated that a high molecular weight and a higher degree of sulfation were essential for their anticoagulant activities. In contrast, not only the polysaccharides but also the depolymerized fragments showed significant FGF/FGFR signal activating activities in a FGF-, molecular weight-, and sulfation-dependent manner. The results presented in current study demonstrated the potential use of the polysaccharides and their fragments as anticoagulants and FGF signal regulators.

In this paper, electromagnetic poly(3,4-ethylenedioxythiophene)/γ-Fe2O3 (PEDOT/γ-Fe2O3) micro-bowls, 1–2 μm in diameter, were prepared by a simple environment-friendly process. In this method, the aqueous solution of cetyltrimethylammonium bromide (CTAB) instead of any organic solvent was used. FeCl3 acted as a source of FeIII for the formation of γ-Fe2O3 and as an oxidant for the polymerization of 3,4-ethylenedioxythiophene (EDOT). The bowl-shaped morphology of PEDOT/γ-Fe2O3 composites was strongly influenced by the concentration of CTAB, FeCl2, ammonia solution and the reaction temperature. The saturation magnetization of PEDOT/γ-Fe2O3 micro-bowls increased with the increase of FeCl2 concentration and reached 6.20 Am2/kg at the FeCl2 concentration of 0.30 mol/L. The conductivity of the PEDOT/γ-Fe2O3 composites was in the range of 101 S/cm. The electrical and magnetic sources of PEDOT/γ-Fe2O3 micro-bowls were confirmed by SEM-EDX, TEM, XRD and XPS spectra. And the possible formation mechanism of PEDOT//γ-Fe2O3 was proposed.

Compared with conventional precipitation polymerization method, cross-linked poly(4-vinylpyridine) (P4VP) and its microgels copolymerized with α -methacrylic acid (MAA) were synthesized through a new route of stabilizer-free polymerization in supercritical fluids. The yellow, dry, fine powders were directly obtained from precipitation polymerization of 4-vinylpyridine in supercritical carbon dioxide (scCO 2 ) at pressures ranging from 70.0 to 230 bar, using N,N′-methylenebisacrylamide as cross-linker. The effects of the reaction pressure, cross-linker ratio, initiator concentration, and reaction time were investigated. The capacity of this microgel for adsorption of copper(II) was also studied. At higher cross-linker concentrations, a high yield of the cross-linked P4VP microgel was generated in scCO 2 , and its particle size was less than 300 nm. Polymerization of cross-linked P4VP in scCO 2 was extremely sensitive to the density of the continuous phase. The adsorption followed the Langmuir isotherm. The adsorption capacities of cross-linked P(4VP- co -MAA) and cross-linked P4VP were 47.2 and 26.9 mg g −1 , respectively.

The temperature-sensitive Cu(II) ion imprinted polymer (Cu(II)-MIIP) materials were prepared via precipitation polymerization methods in supercritical carbon dioxide (scCO2) by using methanol as cosolvent. In the polymerization process, the polymerization mixture consists of copper ion, N-isopropylacrylamide (functional monomer), ethylene glycol dimethacrylate (crosslinker), and 2,2′-azobisisobutyronitrile (initiator). Non-imprinted polymer particles were similarly prepared in the same way except for the presence of copper ion in the polymerization reaction. In this study, the characteristic of swelling/shrinking for Cu(II)-MIIP in response to the change in temperature was investigated by scanning electron microscopy and photograph of swelling/shrinking for Cu(II)-MIIP in deionized water. The above-synthesized polymer particles were characterized by using Fourier transform infrared, thermo-gravimetric analysis, and X-ray diffraction techniques. Furthermore, the complete removal of the copper metal ion from the CuP was confirmed by atomic absorption spectroscopy. The selectivity adsorption of polymer materials was investigated from dilute aqueous solutions, and it was found to have an imprinting efficiency of 2.13 for Zn and Co ions. Copyright © 2011 John Wiley & Sons, Ltd.

An improved chemical one-step method (ICOSM) was used to prepare highly conductive and magnetic polypyrrole/γ-Fe2O3 (PPy/γ-Fe2O3) nanospheres ∼80 nm in diameter. In the reaction process involved, FeCl3 acts as an oxidant for the polymerization of pyrrole and as a source of FeIII for the formation of γ-Fe2O3, which also requires the initial presence of FeII, provided by the addition of FeCl2. The method differs from the previous chemical one-step method (COSM) through the addition of p-toluenesulfonic acid (p-TSA) as the dopant after addition of the FeCl3 solution was finished. The conductive and magnetic properties of PPy/γ-Fe2O3 nanospheres increased and reached maximum values simultaneously with increasing amounts of FeCl2, contrary to the result observed in the previous COSM. The resulting electromagnetic PPy/γ-Fe2O3 nanospheres show maximum conductivity of 64.4 S/cm and saturation magnetization of 4.85 A m2/kg. The p-TSA dopant plays a critical role in the formation of PPy/γ-Fe2O3 nanospheres.

We report the successful precipitation polymerization of 2-hydroxyethyl methacrylate (HEMA) in supercritical carbon dioxide (scCO2) at pressures ranging from 15 to 27 MPa utilizing 2, 2′-azobisisobutyronitrile (AIBN) as a free radical initiator. The effects of the reaction pressure, initiator concentration, monomer concentration, reaction temperature, and reaction time were investigated. Analyses by scanning electron microscopy (SEM) indicated that in all reaction conditions, polymerization in the absence of stabilizer led to the formation of large aggregates of partially coalesced particles, with diameters of approximate 1–10 µm. Analyses by gel permeation chromatography (GPC) indicated that for the reaction pressure, initiator concentration, monomer concentration, reaction temperature, and reaction time studied there are appreciable effect on product molecular weight. Copyright © 2011 John Wiley & Sons, Ltd.

Bilayer nanostructured poly(3,4-ethylenedioxythiophene) (PEDOT) and polyaniline (PANI) conducting polymer composites have been successfully prepared by oxidative polymerization of the parent monomers, aniline (An) and 3,4-ethylenedioxythiophene (EDOT), in aqueous solutions of p-toluenesulfonic acid (p-TSA). As the first step, PANI nanofibers were obtained in the p-TSA solution using ammonium persulfate (APS) as the oxidant. Subsequently, PEDOT was coated onto the PANI nanofibers by the oxidative polymerization of EDOT to form PEDOT/PANI bilayer nanofibers. The resulting nanostructured material was characterized by SEM and a range of spectroscopic methods, which confirmed that the surface layer of the synthesized materials had features typical of chemically synthesized PEDOT. The presence of the PEDOT layer increased the room temperature electrical conductivity of the PEDOT/PANI nanocomposites by 2 orders of magnitude in comparison with the parent PANI nanofibers. Moreover, PEDOT/PANI nanocomposites on a g...

Most functionalized thiophenes are difficult to electropolymerize due to nucleophilicity that will attack the radical cation inhibiting polymerization. However, we have successfully electrodeposited a newly synthesized functionalized terthiophene monomer 3-((2′:2″,5″:2‴-terthiophene)-3″-yl) acrylic acid (TAA) as an active layer of a organic field-effect transistor (OFET). The polymer was then oxidized in order to increase its conductivity. Various oxidizing potentials were experimented and their effect on the OFET's charge mobility was examined. A mobility of 0.25 cm2 (V s)−1 is achieved with an oxidizing potential of 0.9 V after vacuum drying.

Self-assembled polyaniline (PANI) nanotubes were prepared in the presence of three different polymeric acids as dopants, namely poly(4-styrenesulfonic acid) (PSSA), poly(acrylic acid) (PAA) and poly(methyl vinyl ether- alt -maleic acid) (PMVEA) by oxidative polymerization using ammonium persulfate as the oxidant. The molecular structure of polymeric acids had a significant effect on the morphology and size of the polyaniline nanotubes as determined by SEM. The PANI nanotubes were also characterized by FTIR spectroscopy and electron paramagnetic resonance spectroscopy.

Template-free, self-assembled polyaniline (PANI) nanotubes were prepared in a solution of poly(methyl vinyl ether-alt-maleic acid) (PMVEA) by oxidative polymerization using ammonium persulfate as the oxidant. The weight ratio of the polymeric acid to aniline in the solution had a significant effect on the size of the polyaniline nanotubes as determined by SEM. The outer diameter of the nanotubes increased from 65 nm to 160 nm with increased levels of PMVEA in the reaction solution from 1 to 4 wt/v%. The PANI/PMVEA nanotubes were characterized by FTIR and cyclic voltammetry. The nanotubes were used to construct a simple electrochemical oligonucleotide (ODN) sensor where ODN probes were covalently grafted onto the residual carboxylic acid functionalities on the nanotubes. The potential pulse amperometry technique was used to obtain a direct and fast electrochemical readout.

Nanoscaled polyaniline (PANI) fibers with 17-30 nm in diameter were successfully prepared by oxidation polymerization using ferric hydrochloride (FeCl 3 · 6H 2 O) as an oxidant in the presence of p-toluenesulfonic acid (p-TSA), β-naphthalenesulfonic acid (β-NSA), and camphorsulfonic acid (CSA) as the dopants. The resulting nanofibers show smaller diameter, higher crystallinity and conductivity (10 -1 S·cm -1 ) compared with the nanofibers oxidized by ammonium persulfate (APS), which may be due to the lower oxidation/reduction potential of FeCl 3 .

Polyaniline (PANI) nanotubes (130–250 nm in average diameter) doped with α-naphthalene sulfonic acid (α-NSA), β-naphthalene sulfonic acid (β-NSA) and 1,5-naphthalene disulfonic acid were synthesized via a self-assembly process. It was found that the formation yield, morphology (hollow or solid), size, crystalline and electrical properties of the nanostructures are affected by the position and number of –SO3H groups attached to the naphthalene ring of NSA as well as the synthesis conditions. Moreover, these nanotubes aggregate to form a dendritic morphology when the polymerization is performed at a static state. The micelles composed of dopant or dopant/anilinium cations might act in a template-like fashion in forming self-assembled PANI nanotubes, which was further confirmed by X-ray diffraction measurements, while the aggregated morphology of the nanotubes might result from polymer chain interactions including π–π interactions, hydrogen and ionic bonds.

Conducting nanotubes of polyaniline (PANI) about 80–180 nm in diameter were synthesized by a chemical template-free method in the presence of D-10-camphorsulfonic acid (D-CSA) as the dopant, and ammonium persulfate ((NH4)2S2O8) as the oxidant. The effect of synthetic conditions, such as the molar ratio of D-CSA to aniline (An), the concentration of D-CSA in the polymerization media, the reaction temperature and time, on the morphology and size as well as the electrical properties of the PANI–(D-CSA) was investigated. It was found that the above synthetic conditions, especially the molar ratio of D-CSA to An, strongly affected the morphology and formation probability of the resulting PANI. The micelles formed by D-CSA and anilinium cations act as the templates in the formation of PANI–(D-CSA) nanotubes.

Dual functional unimolecular micelles based on a pH-responsive amphiphilic star polymer β-CD-(PLA-b-PDMAEMA-b-PEtOxMA)21 have been developed for the co-delivery of imiquimod and plasmid DNA to dendritic cells. The star polymer with well-defined triblock arms was synthesized by combining activator regenerated by electron-transfer atom-transfer radical polymerization with ring-opening polymerization. Dissipative particle dynamics simulation showed that core-mesophere-shell-type unimolecular micelles could be formed. Imiquimod-loaded micelles had a drug loading of 1.6 wt % and a larger average size (28 nm) than blank micelles (19 nm). The release of imiquimod in vitro was accelerated at the mildly acidic endolysosomal pH (5.0) in comparison to physiologic pH (7.4). Compared with blank micelles, a higher N:P ratio was required for imiquimod-loaded micelles to fully condense DNA into micelleplexes averaging 200–400 nm in size. In comparison to blank micelleplexes, imiquimod-loaded micelleplexes of the same N:P ratio displayed similar or slightly higher efficiency of gene transfection in a mouse dendritic cell line (DC2.4) without cytotoxicity. These results suggest that such pH-responsive unimolecular micelles formed by the well-defined amphiphilic star polymer may serve as promising nano-scale carriers for combined delivery of hydrophobic immunostimulatory drugs (such as imiquimod) and plasmid DNA with potential application in gene-based immunotherapy.

Self‐assembled poly(o‐toluidine) (POT) and poly(o‐anisidine) (POA) hollow spheres were prepared by oxidative polymerization using ammonium persulfate as the oxidant in the presence of 5% by weight of a polymeric acid, poly(methyl vinyl ether‐alt‐maleic acid) (PMVEA). The substituent at the ortho position had a significant effect on the size of the hollow nanospheres as determined by SEM and TEM. The nanospheres were of a very uniform size in the presence of the polymeric acid, with average diameters of 338±25 nm for POT and 210±20 nm for POA. The POT and POA hollow spheres were also characterized by FTIR and UV‐Vis spectroscopy, which confirmed the chemical identity of the substituted polyanilines.

Developing microstructures, such as low molecular aggregates, spherical micelles and multi-compartment micelles, is an expanding area of research in Materials Science. By applying an atom transfer radical polymerization (ATRP) process to cross-linkable fluorinated diblock copolymers and analyzing the data we are able to demonstrate the potential for developing films with different micro-structures for additional biological research. Applying the Dissipative Particle Dynamic (DPD) Method, Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) techniques to cross-linkable fluorinated diblock copolymers of (methyl methacrylate-co-hydroxyethyl methacrylate-co-butyl methacrylate)-b-2-(perfluoroalkyl)ethyl methacrylate (MMA-co-HEMA-co-BMA-b-FMA) we were able to analyze the structures and their relationships to the aggregation of various microstructure formations through the use of various solvents in the process. For the self-assembly of the cross-linkable diblock copolymer in solutions, the DPD simulation results are only in qualitative agreement with experimental data of aggregate morphologies and sizes. This suggests an improved approach to creating materials and methods necessary for studying microstructures in films used in other research areas. Our work examines whether using selective solvents can be easily extended to prepare aggregates with different morphologies, which is an effective shortcut to obtain films with different microstructures. DPD simulation can be considered as an adjunct to experiments and provides other valuable information for the experiment.

Self-assembled poly(o-methoxyaniline) (POMA) hollow nanospheres were prepared in a solution of poly(methyl vinyl ether-alt-maleic acid) (PMVEA) by oxidative polymerization using ammonium persulfate as the oxidant. The weight ratio of PMVEA to o-methoxyaniline in the solution had a significant effect on the morphology of the poly(o-methoxyaniline) nanospheres as determined by scanning electron microscopy. The diameter of the hollow nanospheres decreased from 440 to 210 nm with an increase in the PMVEA concentration from 1% to 5%. Freeze-fracture transmission electron microscopy results showed the presence of spherical micelles composed of PMVEA/ o-methoxyaniline prior to polymerization, which also decreased in size as more PMVEA was added to the solution, and can act as soft templates for the formation of the hollow POMA nanospheres. The POMA/PMVEA hollow nanospheres were characterized by means of Fourier transform infrared, UV-visible, x-ray photoelectron spectroscopy, elemental analysis and conductivity measurements.

Polyaniline (PANI) nanotubes were obtained by a self-assembly process, from a solution containing poly(methyl vinyl ether-alt-maleic acid) (PMVEA) by oxidative polymerization using ammonium persulfate as the oxidant. The size of the nanotubes was greatly affected by the weight ratio of polymeric acid to aniline as measured by SEM images. The outer diameter of the nanotubes increased from 65 to 160 nm as the weight ratio of PMVEA to aniline increased from 1 to 4 wt/wt%. The structural features of the nanotubes were characterized by FTIR, XPS and EPR spectroscopies, which confirmed the presence of the polymeric acid in the PANI nanotubes and their electronic conductive nature. The electrochemical properties were further analysed using cyclic voltammetry.