Polyaniline Dispersions. 6. Stabilization by Colloidal Silica Particles

Abstract

Aniline was polymerized in the presence of ultrafine colloidal silica particles (hydrodynamic diameter 35 nm) in aqueous media and, given a sufficient silica concentration, colloidally stable polyaniline−silica particles were obtained. The particle size of the resulting dispersions was determined by both dynamic light scattering and disk centrifuge photosedimentometry. The typical size of these polyaniline−silica particles is in the range 300−600 nm and is insensitive to the concentration of components in the reaction mixture, temperature, or acidity of the reaction mixture. Particles produced at 0 °C are spherical and their shape becomes less defined when polymerization proceeds at 25 °C. As the silica size is increased, the composite particles become larger and their raspberry morphology more distinct. The electrical conductivity of a typical polyaniline (37.8 wt%)−silica composite is 6.1 × 10-2 S cm-1 at 25 °C. It grows with increasing temperature and does not depend on the frequency in the investigated range from 20 Hz to 1 MHz.

Alumina‐based water‐dispersible conducting nanocomposites of polypyrrole and polypyrrole with poly(N‐vinylcarbazole)

“…Unfortunately, these data fail to suggest any definite trend for the role of oxides in conferring stability on a PNVC suspension in water. In fact, as pointed out by Armes et al, 1 several factors, including preadsorption characteristics of the reacting species on the oxide surface, high surface area, and surface charge on the oxide surface, might be relevant factors controlling the overall stability of the polymer-metal oxide suspensions. However, no definite conclusion on the polymer suspension stability vis-à-vis the nature of the metal oxide dispersant can be drawn from the information available now.…”

“…Considerable research attention globally has been directed to obtaining processible dispersion of these intractable specialty polymers. Armes et al [1][2][3][4][5][6] developed a large variety of PPY-or PANI-based water-dispersible nanocomposites using colloidal SiO 2 and other nanodimensional metal oxides. Biswas and SinhaRay reported on the preparation and evaluation of nanocomposites of PANI, PPY, and poly(N-vinylcarbazole) (PNVC) with montmorillonite clay [7][8][9][10][11] and with nanodimensional metal oxides such as SiO 2 , 12 MnO 2 , 13 and ZrO 2 .…”

A Water Dispersible Nanocomposite of Polyacrylonitrile with Silica via Aqueous Polymerization of Acrylonitrile by K2CrO4–NaAsO2 Redox System

“…However, in presence of nanodimensional SiO 2 particles suspended in the aqueous medium the separated PAN particles encapsulated the SiO 2 particles and thereby formed the composite which remained suspended in the aqueous medium. This process was widely followed by previous workers [4][5][6][7][8][9][11][12][13][14][15][16][17][18][19][20][21][22][23][24] for the preparation of processable dispersions of intractable speciality polymers. The method presented here is expected to be of wide scope since these studies can be extended to miscellaneous water insoluble fundamental polymers including vinyl polymers as well as copolymers of these polymers with the speciality polymers like PPY, PANI, or PTP.…”

Ordered Whiskerlike Polyaniline Grown on the Surface of Mesoporous Carbon and Its Electrochemical Capacitance Performance

“…Spherical PANI particles, for instance, have been obtained by dispersion polymerization in the presence of polymeric stabilizers. [12] Nanotubes or nanofibers of PANI have been prepared by the selfgrowth process. [13,14] Hollow microspheres of PANI have been synthesized by the emulsion method, [15] and nanowires of PANI have been prepared by interfacial polymerization.…”