Preparation and electrochemical capacitance of poly(pyrrole‐co‐aniline)

The copolymer of pyrrole and aniline, poly(pyrrole‐co‐aniline), has been prepared by chemical oxidation of corresponding monomer mixtures with ammonium peroxysulfate. Techniques of FTIR, SEM‐EDS, and BET surface area measurement were used to characterize the structure and morphology of the copolymer. The electrochemical properties of the copolymer were investigated by cyclic voltammetry, galvanostatic charge‐discharge, and electrochemical impedance spectroscopy. The results indicated that poly(pyrrole‐co‐aniline) was about 100–300 nm in diameter and showed better electrochemical capacitive performance than polypyrrole and polyaniline. The specific capacitance of the copolymer electrode was 827 F/g at a current of 8 mA/cm² in 1 mol/L Na₂SO₄ electrolyte. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation and self‐assembly of poly(diglycidyl maleate‐co‐stearyl methacrylate)

Poly(diglycidyl maleate‐co‐stearyl methacrylate) (P(DGMA‐co‐SMA)) with reactive epoxy groups was synthesized by reaction of poly(maleic anhydride‐co‐stearyl methacrylate) (P(MA‐co‐SMA)) and epichlorohydrin. The effect of precipitant on self‐assembly behaviors of the resultant copolymer was investigated. It was found that vesicles and nanotubule liked aggregates can be obtained through self‐assembly of P(DGMA‐co‐SMA) in THF solution using CH₃CH₂OH (EtOH) as precipitant while spheral aggregates can be obtained using H₂O as precipitant. The mechanism of the self‐assembly behavior was discussed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Emulsifier‐free synthesis and self‐assembly of an amphiphilic poly(styrene‐co‐acrylic acid) copolymer

A poly(styrene‐co‐acrylic acid) copolymer was synthesized by surfactant‐free polymerization with the assistance of power ultrasound in water. Fourier transform infrared, NMR, and differential scanning calorimetry measurements revealed that the copolymer was random. Atomic force microscopy and laser light scattering were used to investigate the self‐assembly of the copolymer, and it was found that the copolymer chains formed micelles or other self‐assemble structures in solution. Atomic force microscopy also indicated that the self‐assembled structures developed into nanospheres with a poly(acrylic acid)‐rich or polystyrene‐rich surface in a film, depending on the solvent used for the preparation of the film. In particular, a wheel‐like structure could resulted in a film when the copolymer film was prepared in a moist environment; it resulted from heterogeneous aggregates of poly(acrylic acid) at the rim of water bubbles. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100:3718–3726, 2006     

Synthesis and physicochemical characterization of amphiphilic block copolymer self‐aggregates formed by poly(ethylene glycol)‐block‐poly(ϵ‐caprolactone)

Diblock copolymers with different poly(ε‐caprolactone) (PCL) block lengths were synthesized by ring‐opening polymerization of ε‐caprolactone in the presence of monomethoxy poly(ethylene glycol) (mPEG‐OH, MW 2000) as initiator. The self‐aggregation behaviors and microscopic characteristics of the diblock copolymer self‐aggregates, prepared by the diafiltration method, were investigated by using ¹H NMR, dynamic light scattering (DLS), and fluorescence spectroscopy. The PEG–PCL block copolymers formed the self‐aggregate in an aqueous environment by intra‐ and/or intermolecular association between hydrophobic PCL chains. The critical aggregation concentrations of the block copolymer self‐aggregate became lower with increasing hydrophobic PCL block length. On the other hand, reverse trends of mean hydrodynamic diameters were measured by DLS owing to the increasing bulkiness of the hydrophobic chains and hydrophobic interaction between the PCL microdomains. The partition equilibrium constants (K_v) of pyrene, measured by fluorescence spectroscopy, revealed that the inner core hydrophobicity of the nanoparticles increased with increasing PCL chain length. The aggregation number of PCL chain per one hydrophobic microdomain, investigated by the fluorescence quenching method using cetylpyridinium chloride as a quencher, revealed that 4–20 block copolymer chains were needed to form a hydrophobic microdomain, depending on PCL block length. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3520–3527, 2006     

Influence of different dopants on the adsorption,morphology, and properties of self‐assembled films of poly(o‐ethoxyaniline)

Self‐assembled films of poly(o‐ethoxyaniline)—POEA alternated with sulfonated lignin (SL)—were successfully produced, and their kinetics of formation and growth investigated for different dopants (hydrochloric acid, methanesulfonic acid, p‐toluenesulfonic acid, and camphorsulfonic acid). These films were characterized by ultraviolet‐visible spectroscopy, atomic force microscopy, surface potential, and electrical resistance measurements. It has been observed that the bulkiest dopants led to a greater time for the polymer deposition and greater amount of material adsorbed. This can be explained by the lower mobility and lower solvation of the bulkiest dopant counterions, which led to a higher screening effect of the charges present in the POEA chains and therefore to a more compact molecular conformation. The morphology of the POEA films were also greatly affected by the type of dopant used, being rougher for the bulkiest dopants. The POEA films also exhibited different electrical responses upon ethylene exposure depending on the dopant, indicating a promising use for gas sensor applications. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1309–1316, 2002     

Amphiphilic block copolymer poly(lactic acid)‐block‐(glycidylazide polymer)‐block‐polystyrene: synthesis and self‐assembly

The triblock energetic copolymer poly(lactic acid)‐block‐(glycidylazide polymer)‐block‐polystyrene (PLA‐b‐GAP‐b‐PS) was synthesized successfully through atom‐transfer radical polymerization (ATRP) of styrene and ring‐opening polymerization of d,l ‐lactide. The energetic macroinitiator GAP‐Br, which was made from reacting equimolar GAP with α‐bromoisobutyryl bromide, firstly triggered the ATRP of styrene with its bromide group, and then the hydroxyl group on the GAP end of the resulting diblock copolymer participated in the polymerization of lactide in the presence of stannous octoate. The triblock copolymer PLA‐b‐GAP‐b‐PS had a narrow distribution of molecular weight. In the copolymer, the PS block was solvophilic in toluene and improved the stability of the structure, the PLA block was solvophobic in toluene and served as the sacrificial component for the preparation of porous materials, and GAP was the basic and energetic material. The three blocks of the copolymer were fundamentally thermodynamically immiscible, which led to the self‐assembly of the block copolymer in solution. Further studies showed that the concentration and solubility of the copolymer and the polarity of the solvent affected the morphology and size of the micelles generated from the self‐assembly of PLA‐b‐GAP‐b‐PS. The micelles generated in organic solvents at 10 mg mL^?1 copolymer concentration were spherical but became irregular when water was used as a co‐solvent. The spherical micelles self‐assembled in toluene had three distinct layers, with the diameter of the micelles increasing from 60 to 250 nm as the concentration of the copolymer increased from 5 to 15 mg L^?1. © 2017 Society of Chemical Industry     

Self‐assembled poly(styrene‐co‐N‐isopropylacrylamide) film induced by capillary force

The monodisperse poly(styrene‐co‐N‐isopropylacrylamide) (poly(St‐co‐NIPAAm)) particles prepared by emulsifier‐free emulsion polymerization with microwave irradiation were induced by capillary forces to self‐assemble, and formed the two‐dimensional films on the clean glassware wafer substrates. The morphologies of the two‐dimensional films were characterized by scanning electron microscopy (SEM) and atom force microscopy (AFM). The results showed that monodisperse poly(St‐co‐NIPAAm) particles could form ordered two‐dimensional films by capillary forces. With NIPAAm concentration increasing, there gradually appeared surface undulations or surface defective region on the two‐dimensional films. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3514–3519, 2006     

Electrospun self‐assembled nanofiber yarns

A technique for making self‐assembled electrospun (E‐spun) nanofiber yarns from poly(acrylonitrile) in a single step is described. The process involved formation of the nanofiber yarn directly within the electrospinning zone and its removal before it can reach the counter‐electrode. The yarn is presumably formed due to splitting of the main jet into numerous nanojets and their reassembly into a single entity midway between the two electrodes. The process was found to occur at a particular field strength, which varied considerably with the concentration of the polymer dope. The gross morphology of yarns and the alignment of nanofibers in the yarn were evaluated by scanning electron microscopy (SEM). The rationale behind the formation of the yarn like structure has been explained. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Electrochemical synthesis and characterization of poly(pyrrole‐co‐ε‐caprolactone) conducting copolymer

The direct electrochemical copolymerization of pyrrole (Py) and ε‐caprolactone at various monomer ratios was carried out by potentiostatic methods in nitromethane. Characterizations of the novel copolymer were based on scanning electron microscopy, differential scanning calorimetry, thermal gravimetrical analysis, cyclic voltammetry, electrochemical impedance spectroscopy, Fourier transform infrared spectra, and elemental analysis studies. The results showed that the electrochemical oxidation of Py and ε‐caprolactone comonomers generated true copolymers rather than blends of the two homopolymers. The electrical conductivity of the copolymers increased with the amount of polypyrrole in the copolymer between the value of 8.2 S/cm and 0.6 S/cm. A probable mechanism of copolymerization was proposed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Self‐assembled structures in polystyrene‐block‐polyisoprene‐blend‐polystyrene and polystyrene‐block‐poly(methyl methacrylate)‐blend‐polystyrene or ‐blend‐poly(methyl methacrylate) in the strong segregation regime

This study deals with the investigation of microphase‐separated morphology and phase behaviour in blends of polystyrene‐block‐polyisoprene with homopolystyrene and blends of polystyrene‐block‐poly(methyl methacrylate) with homopoly(methyl methacrylate) or homopolystyrene in the strong segregation regime using small‐angle X‐ray scattering and transmission electron microscopy as a function of composition, molecular weight of homopolymers, r_M and temperature. Parameter r_M = M_H/M_C (where M_H is the molecular weight of homopolymer and M_C that of the corresponding block copolymer) was selected to encompass behaviour of the chains denoted as a ‘wet brush’ (i.e. r_M < 1). The relative domain spacing D/D_o increases in the regime 0 < r_M?1 with increasing concentration of homopolymer w_P and increasing r_M but depends on the specific implemented morphology. We tested a new approximate D/D_o versus w_P relation in the strong segregation regime using block copolymers of high molecular weights. It is shown that the parameters r_M and χ^3/2N determine the slope of the D/D_o versus w_P relation in the strong segregation regime and the new approximation generally matches the experimental data better than the approximations used so far. Copyright © 2010 Society of Chemical Industry     

Amphiphilic linear–hyperbranched polymer poly(ethylene glycol)–branched polyethylenimine–poly(ϵ‐caprolactone): synthesis,self‐assembly and application as stabilizer of platinum nanoparticles

Amphiphilic linear–hyperbranched polymer poly(ethylene glycol)–branched polyethylenimine–poly(?‐caprolactone) (PEG‐PEI‐PCL) was synthesized by progressively conjugating PEG (one chain) and PCL (multi‐chains) to PEI (hyperbranched architecture) with a yield of 87%. PEG‐PEI‐PCL forms nano‐sized uniform spherical micelles by self‐assembly in water. The micelles had an average diameter of 56 nm determined using dynamic light scattering and 35 nm observed from transmission electron microscopy images. PEG‐PEI‐PCL was used as a stabilizer of platinum nanoparticles (PtNPs) for the first time. The particle diameter of PEG‐PEI‐PCL‐stabilized PtNPs was 7.8 ± 1.4 nm. Amphiphilic (hydrophilic–hydrophilic–hydrophobic) and hyperbranched (linear–hyperbranched–grafted) structures enabled PtNPs to effectively stabilize and disperse in liquid‐phase synthesis. The highly disperse PtNPs in PEG‐PEI‐PCL micelles improved the catalytic activity for the reduction of 4‐nitrophenol with a catalytic yield of near 100%. © 2016 Society of Chemical Industry     

Layer‐by‐layer self‐assembled multilayer films of single‐walled carbon nanotubes and tin disulfide nanoparticles with chitosan for the fabrication of biosensors

In this study, multilayer films containing chitosan, tin disulfide (SnS₂) nanoparticles, and single‐walled carbon nanotubes were prepared on glassy carbon electrodes with the use of a layer‐by‐layer assembly technique. The resulting films were characterized with cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy, and ultraviolet–visible absorption spectroscopy. The results of CV and EIS indicates that the peak currents and charge‐transfer resistance all had linear responses to the number of assembled layers. The multilayer‐film‐modified electrode showed excellent electrocatalytic properties for some species, such as dopamine hydrochloride (DA), ascorbic acid (AA), and uric acid (UA). The well‐separated voltammetric signals of DA, UA, and AA could be obtained on the assembled multilayer‐film‐modified electrode, and the peak‐to‐peak potential separations were 171, 136, and 307 mV for DA–UA, DA–AA, and UA–AA on CV, respectively. These facts showed that the multilayer‐film‐modified electrode could be used as a new sensor for the simultaneous detection of DA and UA in the presence of AA in a real sample. In addition, the multilayer films were stable, selective, and reproducible. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Studies on the dielectric properties of poly(o‐toluidine) and poly(o‐toluidine‐aniline) copolymer

Poly(o‐toluidine) (PoT) and poly(o‐toluidine co aniline) were prepared by using ammonium persulfate initiator, in the presence of 1M HCl. It was dried under different conditions: room temperature drying (48 h), oven drying (at 50°C for 12 h), or vacuum drying (under vacuum, at room temperature for 16 h). The dielectric properties, such as dielectric loss, conductivity, dielectric constant, dielectric heating coefficient, loss tangent, etc., were studied at microwave frequencies. A cavity perturbation technique was used for the study. The dielectric properties were found to be related to the frequency and drying conditions. Also, the copolymer showed better properties compared to PoT alone. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 592–598, 2004     

Growth control and long‐range self‐assembly of poly(methyl methacrylate) nanospheres

A systematic investigation of the reaction time and role of a cosolvent (toluene) in inducing several beneficial effects on nanobead properties was performed to achieve the synthesis of poly(methyl methacrylate) nanospheres. In particular, good dimensional control in the range of 100–400 nm, very low polydispersity, and a spherical shape were consistently obtained. Different parameters affecting the self‐assembly mechanism leading to the deposition of hard‐sphere photonic crystals were studied, and the features underlying their role were examined. Photonic crystals were produced by the evaporation of nanosphere suspensions at different temperatures, relative humidities, and suspension ionic strengths and with different substrate materials. The proper conditions for obtaining large crystal domains were determined. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4493–4499, 2006     

Polyaniline self‐assembled with DTPA: Facilely tuned morphology and properties

The effects of pH profile and “soft template” during aniline chemical oxidative polymerization (COP) were investigated and evaluated simultaneously with diethylene triamine pentaacetic acid (DTPA) as a structural directing agent. Formation of PANI nanotubes and nanoparticles, smooth microspheres, and urchin‐like microspheres were illustrated by evaluating the pH profile during aniline COP while considering the “soft template” effects of DTPA. PANI nanosheets with two semicurled edges were found in the system producing nanotubes, which provides an evidence for the “curling mechanism” of PANI nanotube formation. With different pH profiles, chemical structures and aggregation structures of the as‐synthesized PANI micro/nanostructures are similar, whereas their conductivity, wettability, Cr (VI) adsorption, and electrochemical behaviors are distinct. The present study indicates that if properly conducted, pH profile adjustment is more effective than “soft template” to control the morphology and to optimize the performance of PANI micro/nanostructures. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42403.     

Surface modification using self‐assembled layers of amphiphilic cyclodextrins

In this study six amphiphilic cyclodextrin derivatives were prepared by esterification and used to coat five industrial products made from polypropylene, polyethylene, polyvinyl chloride, or polyurethane using a new, patented coating technology. This simple approach, which consists merely of dipping the material to be coated into a suspension of a given cyclodextrin derivative in an ethanol/water solution, was used to functionalize support materials with a coat that is stable in aqueous solutions and which renders the coated materials hydrophilic. The functionalization proved to be controllable in terms of amount of cyclodextrin on the surface and can be implemented in existing production lines without investment in advanced production equipment. It is hypothesized that the cyclodextrins order themselves in structured layers forming channel‐like structures preserving the very large potential for uptake and release of active compounds that is known to cyclodextrins. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41047.     

Nanophase morphology and crystallization in poly(vinylidene fluoride)/polydimethylsiloxane‐block‐poly(methyl methacrylate)‐block‐polystyrene blends

An approach to achieve confined crystallization of ferroelectric semicrystalline poly(vinylidene fluoride) (PVDF) was investigated. A novel polydimethylsiloxane‐block‐poly(methyl methacrylate)‐block‐polystyrene (PDMS‐b‐PMMA‐b‐PS) triblock copolymer was synthesized by the atom‐transfer radical polymerization method and blended with PVDF. Miscibility, crystallization and morphology of the PVDF/PDMS‐b‐PMMA‐b‐PS blends were studied within the whole range of concentration. In this A‐b‐B‐b‐C/D type of triblock copolymer/homopolymer system, crystallizable PVDF (D) and PMMA (B) middle block are miscible because of specific intermolecular interactions while A block (PDMS) and C block (PS) are immiscible with PVDF. Nanostructured morphology is formed via self‐assembly, displaying a variety of phase structures and semicrystalline morphologies. Crystallization at 145 °C reveals that both α and β crystalline phases of PVDF are present in PVDF/PDMS‐b‐PMMA‐b‐PS blends. Incorporation of the triblock copolymer decreases the degree of crystallization and enhances the proportion of β to α phase of semicrystalline PVDF. Introduction of PDMS‐b‐PMMA‐b‐PS triblock copolymer to PVDF makes the crystalline structures compact and confines the crystal size. Moreover, small‐angle X‐ray scattering results indicate that the immiscible PDMS as a soft block and PS as a hard block are localized in PVDF crystalline structures. © 2019 Society of Chemical Industry     

Nanophase morphology and crystallization in poly(vinylidene fluoride)/polydimethylsiloxane‐block‐poly(methyl methacrylate) blends

A polydimethylsiloxane‐block‐poly(methyl methacrylate) (PDMS‐b‐PMMA) diblock copolymer was synthesized by the atom transfer radical polymerization method and blended with a high‐molecular‐weight poly(vinylidene fluoride) (PVDF). In this A‐b‐B/C type of diblock copolymer/homopolymer system, semi‐crystallizable PVDF (C) and PMMA (B) block are miscible due to favorable intermolecular interactions. However, the A block (PDMS) is immiscible with PVDF and therefore generates nanostructured morphology via self‐assembly. Crystallization study reveals that both α and γ crystalline phases of PVDF are present in the blends with up to 30 wt% of PDMS‐b‐PMMA block copolymer. Adding 10 wt% of PVDF to PDMS‐b‐PMMA diblock copolymer leads to worm‐like micelle morphology of PDMS of 10 nm in diameter and tens of nanometers in length. Moreover, morphological results show that PDMS nanostructures are localized in the inter‐fibrillar region of PVDF with the addition of up to 20 wt% of the block copolymer. Increase of PVDF long period by 45% and decrease of degree of crystallization by 34% confirm the localization of PDMS in the PVDF inter‐fibrillar region. © 2018 Society of Chemical Industry     

Controllable self‐assembly of polystyrene‐block‐poly(2‐vinylpyridine)

Block copolymers can form various ordered structures by self‐assembly, and their composites with inorganic materials may give surprising properties. This review summarizes recent developments in the preparation, mechanism and application of various types of self‐assembly of polystyrene‐block‐poly(2‐vinylpyridine) (PS‐b‐P2VP). The focus of the review is on how to control the self‐assembly of the dynamic and ordered structure of PS‐b‐P2VP based materials by applying effective factors such as thermal annealing, solvent annealing, block composition and blending. Moreover, the combination of the self‐assembly of PS‐b‐P2VP and various nanoparticles, with potentials in drug delivery, sensors and catalysis, is highlighted. © 2018 Society of Chemical Industry     

Cationic amphiphilic copolymers: synthesis,characterization, self‐assembly and drug‐loading capacity

Amphiphilic copolymers with cationic hydrophilic moieties and different ratios of hydrophobic portion to hydrophilic portion were designed and synthesized via the combination of hydrosilylation reactions and quaternization reactions. The structures were characterized through Fourier transform infrared spectroscopy, ¹H NMR , ¹³C NMR and gel permeation chromatography. The measurements of critical micelle concentrations, electrical conductivities and zeta potentials indicated that the copolymers could self‐assemble into nanoparticles with charges around the surface in aqueous solution. The sizes of the micelles were between 67 nm and 104 nm detected by dynamic light scattering. The self‐assembled micelles were used as drug carriers to encapsulate a model drug (tocopherol), and their drug‐loading content (DLC ) and efficiency (DLE ) were determined by UV ?visible spectra, resulting in considerable drug‐loading capacity to a tocopherol maximum up to 17.2% (DLC ) and 80.3% (DLE ) with a size of 90 nm. The blank micelles and drug‐loaded micelles displayed a spherical shape detected by transmission electron microscopy, which demonstrated not only the self‐assembly behaviors but also the drug‐loading performances of the cationic amphiphilic copolymers. All the results demonstrated that the cationic amphiphilic copolymers could be used as potential electric‐responsive drug carriers. © 2017 Society of Chemical Industry