Polyaniline–Silica Composite Conductive Capsules and Hollow Spheres

Abstract

In this paper, we report on the preparation of monodisperse polyaniline (PANi)–silica composite capsules and hollow spheres on monodisperse core–gel‐shell template particles. An extension of the previously reported inward growth method was used. The samples were self‐stabilized without external additives. The core–gel‐shell particles were prepared by the inward sulfonation of monodisperse polystyrene particles. The introduced sulfonic acid and sulfone groups are responsible for the gel properties. The gel‐shell thickness and core size were synchronously controlled over the whole particle radius range. After aniline (ANi) monomer was preferentially absorbed in the sulfonated polystyrene shell, PANi was formed by polymerization. PANi was doped in situ with a sulfonic acid group to give the capsules a high conductivity. PANi hollow spheres were derived after the polystyrene cores were dissolved: their cavity size and shell thickness were synchronously controlled by using different core–gel‐shell particles. The PANi–silica composite capsules and hollow spheres were therefore prepared by a sol–gel process using tetraethylorthosilicate in the conducting shell. The PANi shell became more robust while maintaining the same conductivity level. Morphological results indicate that the PANi and silica formed a bicontinuous network. Fourier‐transform infrared (FTIR) spectra revealed that the hydrogen bonding in the PANi–gel shell was enhanced after the silica phase was incorporated, which could explain the high conductivity level after the silica phase was added. In a converse procedure, silica capsules and hollow spheres were prepared by a sol–gel process that incorporated tetraethylorthosilicate into the core–gel‐shell templates, which was followed by the absorption and polymerization of aniline in the silica shell thus forming PANi–silica composite capsules and hollow spheres. The silica capsules and hollow spheres thereby became conductive.

Composite silica nanoparticle/polyelectrolyte microcapsules with reduced permeability and enhanced ultrasound sensitivity

“…15,17,18 The exceptional mechanical properties of silica nanoparticles also make them attractive candidates for functional molecular assemblies. [19][20][21][22] Most efforts of design and synthesis of inorganic/organic composite capsules have been focused on assembling prefabricated inorganic nanoparticles into the soft PE multilayer shell. [23][24][25] This method could produce capsules with relative good control over capsule size, stability and stimuli responsive property, but has considerable challenges in encapsulating and releasing low-molecularweight molecules (including drugs) from LbL capsules.…”

Successful ATRP Syntheses of Amphiphilic Block Copolymers Poly(styrene-block-N,N-dimethylacrylamide) and Their Self-assembly

“…4 Although hollow particles were often prepared by the polymer deposition onto a degradable particle substrate and following removal of the substrate, 5,6 these two-step methods are so complicated that one-step self-assembly method may be of scientific and industrial importance. The self-assembly of the polymer chains efficiently formed soft nanomatters based on multiple intermolecular interactions of the long chain, giving a higher stability than the case of low-mass molecule assembly.…”

Photo-catalytic Removal of Methyl Orange Dye by Polyaniline Modified ZnO using Visible Radiation

“…The peaks of the PANI around 1575 cm -1 , 1497 cm -1 , 1298 cm -1 and 1151 cm -1 are shifted to 1567 cm -1 , 1482 cm -1 , 1289 cm -1 and 1132 cm -1 respectively. These shifts of characteristic peaks of the PANI may be the result of the interactions between the PANI chains and ZnO nanoparticles which affect the electron densities and bond energies of the PANI (Somani et al, 1999 andNiu et al, 2003). The shifting to the lower wave numbers shows the increasing the electron density of PANI chains or due to the action of hydrogen bonding between the hydroxyl groups on the surface of ZnO nanoparticles and the amine groups in the PANI molecular chains (He, 2005).…”