The paper reports a facile synthesis of novel anionic spherical polymer brushes which was based on grafting sodium 2-acrylamido-2-methylpropane-1-sulfonate from the surface of 4,4′-Azobis (4-cyanopentanoyl chloride)-modified carbon spheres. Various characterization methods involving a scanning electron microscope, energy dispersive X-ray spectroscopy, Fourier transform infrared spectrum, and thermo-gravimetric analysis were utilized to analyze the morphology, chemical composition, bonding structure, and thermal stability, respectively. The molecular weight (Mw) and polydispersity (Mw/Mn) of brushes were 616,000 g/mol and 1.72 determined by gel permeation chromatography experiments. Moreover, the dispersibility of ASPB in water and in the presence of aqueous NaCl solutions of different concentrations was investigated. Results show that the dispersibility of carbon spheres has been enhanced owing to grafted polyelectrolyte chains, while the zeta potential of the particle decreases and its brush layer shrinks upon exposure to sodium ions (Na+).

As the criteria of energy conservation, emission reduction, and environmental protection become more important, and with the development of wet-end papermaking, developing excellent retention aids is of great significance. Spherical polyelectrolyte brushes (SPBs) bearing polyelectrolyte chains grafted densely to the surface of core particle have the potential to be novel retention aids in wet-end papermaking not only because of their spherical structure, but also due to controllable grafting density and molecular weight. Such characteristics are crucial in order to design multi-functional retention aids in sophisticated papermaking systems. This review presents some important recent advances with respect to retention aids, including single-component system and dual-component systems. Then, basic theory in papermaking is also briefly reviewed. Based on these advances, it emphatically describes spherical polyelectrolyte brushes, focused on their preparation methods, characterization, conformation, and applications in papermaking. This work is expected to contribute to improve a comprehensive understanding on the composition, properties, and function mechanisms of retention aids, which helps in the further investigation on the design of novel retention aids with excellent performance.

Spherical polymer brushes were synthesized by grafting acrylamide from the surface of γ-methacryloxypropyl trimethoxy-silane-modified SiO2 nanoparticles. Then, cationic spherical polyacrylamide (CSPAM) brushes were obtained by a manniched polyacrylamide (PAM). Fourier-transform infrared spectroscopy, transmission electron microscopy, thermogravimetric analysis, and gel permeation chromatography were introduced to analyze the structure, morphology, and molecular weight of CSPAM, respectively. The effects of pH and the dosage of CSPAM on the flocculation of fine pulp and precipitated calcium carbonate were studied. Furthermore, the optimal drainage performance could be achieved when the beating degree (°SR) decreased by about 14.42% with the dosage of CSPAM of 2 mg·g−1. The retention effect of CSPAM revealed that the highest first-pass retention was 71.1% when the dosage of CSPAM was 3.5 mg·g−1. In addition, the mechanism of retention and drainage of CSPAM was discussed.

Owing to their special structure and excellent physical and chemical properties, conducting polymers have attracted increasing attention in materials science. In recent years, tremendous efforts have been devoted to improving the comprehensive performance of conducting polymers by using the technique of “doping.” Spherical polyelectrolyte brushes (SPBs) bearing polyelectrolyte chains grafted densely to the surface of core particles have the potential to be novel dopant of conducting polymers not only because of their spherical structure, high grafting density and high charge density, but also due to the possibility of their being applied in printed electronics. This review first presents a summary of the general dopants of conducting polymers. Meanwhile, conducting polymers doped with spherical polyelectrolyte brushes (SPBs) is highlighted, including the preparation, characterization, performance and doping mechanism. It is demonstrated that comprehensive performance of conducting polymers has improved with the addition of SPBs, which act as template and dopant in the synthesis of composites. Furthermore, the applications and future developments of conductive composites are also briefly reviewed and proposed, which would draw more attention to this field.

A series of polypyrrole (PPy) doped with anionic spherical polyelectrolyte brushes (ASPB) (PPy/ASPB composite) at different polymerization variables (the amount of ASPB, molecular weight of grafted chains, polymerization time, and polymerization temperature) were synthesized by means of chemical oxidative polymerization, characterized with FTIR and analyzed by electrical conductivity measurements. Results verified that long grafted chains and low temperature helped to increase the electrical conductivity. ASPB acted both as dopant and as template in the polymerization process as a result of offering favorable space factors for the growth of pyrrole.

A facile preparation of novel salt responsive spherical polymer brushes (SPB) consisting of a carbon spheres core and a shell of sodium polystyrene sulfonate (PSSNa) was described. The SPB were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The radius R of carbon spheres and hydrodynamic radius Rh of SPB were ca. 370 nm and 785 nm, respectively. The brushes had Mw of 393600 g/mol with polydispersity Mw/Mn of 1.58. Furthermore, the dependence of PSSNa brushes on ionic strength and pH was investigated.

Novel cationic spherical polyelectrolyte brushes (CSPB) consisting of γ-methacryloxypropyl trimethoxy-silane (KH-570) modified SiO2cores and poly (Dimethyl diallyl ammonium chloride) (PDMDAAC) brushes were prepared by conventional free radical polymerization. The resulting CSPB were characterized by Fourier transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), and Thermo-gravimetric analysis (TGA). After cleaving the polyelectrolyte chains from the anchoring surface, the molecular weight of brushes was 1.824×103gmol-1from Gel Permeation Chromatography (GPC) measurements.

A novel polyaniline–anionic spherical polyelectrolyte brushes (PANI/ASPB) nanocomposite was synthesised by means of chemical oxidative polymerisation. Different characterisation and analytical methods involving scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction and thermo-gravimetric analysis confirmed that anionic spherical polyelectrolyte brushes served both as a dopant and as a template. While polyaniline (PANI) nanocomposites have a ‘rod-like’ or fibrillar morphology, the PANI/ASPB nanocomposite displayed a sphere-like structure. The room temperature electrical conductivity of the PANI/ASPB nanocomposite was 26.3 S/cm, which is higher than that of PANI (7.1 S/cm). In addition, PANI/ASPB nanocomposites possessed enhanced thermal stability and good solubility properties.

The synthesis procedure and dopant are crucial to the electrical conductivity, thermal stability, and solubility properties of polyaniline (PANI). In this paper, high-performance PANI was synthesized by means of chemical oxidative polymerization using anionic spherical polyelectrolyte brushes (ASPB) as dopant. The bonding structure, crystallographic structure, morphology, and thermal stability of the conductive nanocomposite were analyzed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermo-gravimetric analysis (TGA) respectively. Meanwhile, investigation on the electrical conductivity suggested that the room-temperature electrical conductivity of PANI doped with ASPB (PANI/ASPB) was 19.3 S/cm, which was higher than that of PANI (7.0 S/cm), PANI doped with poly(sodium-p-styrenesulfonate) (PSS) (PANI/PSS) (14.6 S/cm), PANI doped with SiO2 (PANI/SiO2) (18.2 S/cm), and PANI doped with canonic spherical polyelectrolyte brushes (CSPB) (PANI/CSPB) (8.0 S/cm). Meanwhile, the addition of ASPB improved the thermal stability and solubility properties of PANI. ASPB played the role of template. Conductive mechanism of PANI/ASPB nanocomposite can be explained by the theoretical models of three-dimensional variable range-hopping (3D VRH).

The extent to which anionic spherical polyelectrolyte brushes (ASPB) as dopant improved the performance of polyaniline-polypyrrole (PANI-PPy) nanocomposite was investigated. Different characterization and analytical methods including Fourier transform infrared spectroscopy (FTIR), thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM), and X-ray diffraction (XRD) confirmed that ASPB serving as dopant could improve the comprehensive properties of PANI-PPy nanocomposite. It was different from dopants such as SiO2, poly(sodium-p-styrenesulfonate) (PSS), and canonic spherical polyelectrolyte brushes (CSPB) which only enhanced the performance of PANI-PPy nanocomposite on one or two sides. The electrical conductivity of (PANI-PPy)/ASPB nanocomposite at room temperature was 8.3 S/cm, which was higher than that of PANI-PPy (2.1 S/cm), (PANI-PPy)/PSS (6.8 S/cm), (PANI-PPy)/SiO2 (7.2 S/cm), and (PANI-PPy)/CSPB (2.2 S/cm). Meanwhile, (PANI-PPy)/ASPB nanocomposite possessed enhanced thermal stability and good solubility. In addition, the effects of polymerization temperature, the molecular weight of grafted polyelectrolyte brushes, and storage time on electrical conductivity were discussed.

A poly(aniline‐co‐pyrrole), using anionic spherical polyelectrolyte brushes (ASPB) as dopant and template, was synthesized by chemical oxidation polymerization. The composites were characterized by scanning electron microscopy (SEM), Fourier‐transform infrared spectrometry (FTIR), X‐ray diffraction (XRD), and electrical studies. The SEM images confirmed that the composites had a spherical‐like structure, with a size of ca. 170 nm. The FTIR spectra showed the intermolecular interaction between poly(aniline‐co‐pyrrole) and ASPB. The XRD analysis revealed that the interplanar distance of the copolymers increased from 0.373 nm to 0.391 nm. The electrical conductivity of the poly(aniline‐co‐pyrrole)/ASPB nanocomposites at room temperature was 8.3 S cm−1, higher than that of the conducting copolymers (2.1 S cm−1). These conductive nanocomposites have nanoparticle size, controllable morphology, and the potential for application in inkjet electronic printing. POLYM. COMPOS., 35:1858–1863, 2014. © 2014 Society of Plastics Engineers

The synthesis of spherical polymer brushes consisting of a nano-SiO2 core modified by γ-methacryloxypropyl trimethoxy-silane and a shell of linear polyacrylamide by grafting polymerization was described. The spherical polymer brushes were characterized by Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and Thermo-gravimetric analysis (TGA). After cleavage of the ester group that connected the polymers to the surface, the molecular weight of the brushes was determined by Gel Permeation Chromatography (GPC). The results showed that the average diameter of spherical polymer brushes was ca. 140 nm while weight average molecular weight and surface grafting density were 1.407 × 103 g/mol and 1.016 × 10−4 mol/g respectively.

Novel cationic spherical polyelectrolyte brushes (CSPBs) were prepared by photoemulsion polymerization. Dimethyl diallyl ammonium chloride was grafted onto the surface of polystyrene particles bearing a thin layer of photoinitiator that was prepared by Schotten-Baumann reaction of Darocur 1173 and Methacryloyl chloride. Transmission electron microscopy (TEM) was used to analyze the size and shape of CSPBs, the average diameter of these particles with uniform spherical structure was ca.170nm. A link to the use of this system as a model for retention and drainage aid in the papermaking process was described. Dynamic drainage experiment indicated that the shortest drainage time was 23.2s when the percentage of the aid was 0.04%(wt). The retention effect of the aid was tested that the highest of the first-pass retention was 70.89% when the percentage of aid was 0.035%(wt).