Adsorption of poly(3-octylthiophene) nanoparticles on cellulose fibres: Effect of dispersion stability and fibre pre-treatment with carboxymethyl cellulose

The impact of miniemulsified poly(3-octylthiophene) (P3OT) nanoparticles stability on their adsorption on softwood cellulose fibres was investigated. Dilution in water of the corresponding cationic nanoparticles suspension led to a progressive aggregation attributed to the tetradecyltrimethylammonium bromide surfactant (TTAB) depletion from the particles surface. In the presence of diluted fibres suspension, aggregation occurred in water (solvent) but also at the fibres surface. Such phenomenon was explained by the neutralization of the anionic moieties borne on the fibre surface (carboxylic groups) by the cationic particles and to the onset of attractive interactions among particles. When the dilution factor (or the global volume) increased, a less pronounced surface aggregation between particles was attributed to a slower particles diffusion rate. Fibres functionalization was improved by increasing their negative charge by a pre-treatment with carboxymethyl cellulose. Highly conductive iodine-doped pellets (2–6 × 10−4 S/cm) were obtained from treated fibres. Pellets conductivity sharply decreased upon aging, reflecting the progressive P3OT de-doping and/or “over-oxidation” by atmospheric O2.