One-Step Preparation of Superhydrophobic Polyaniline/Sodium Dodecylbenzenesulfonate Composites

Superhydrophobic polyaniline (PANI)/sodium dodecylbenzenesulfonate (SDBS) composites were fabricated in one-step, by the oxidative polymerization of aniline in the presence of SDBS. The morphology and elemental composition of the PANI/SDBS composite were characterized by field-emission scanning electron microscopy. The chemical structure was confirmed by Fourier transform-infrared spectroscopy, ultraviolet-visible spectrophotometry, and X-ray powder diffraction. The superhydrophilic and superhydrophobic properties of the PANI/SDBS composite were determined from water contact angle (WCA) measurements, and were dependent on SDBS concentration, pH, and composite morphology. The formation and superhydrophobic mechanism of the PANI/SDBS composite are discussed. The composite surface had a WCA of >150 degrees at pH 1-9 and SDBS concentration more than 0.016 mol.L-1. SDBS doping resulted in a 98% conversion of the aniline monomer. The superhydrophobic PANI/SDBS composite formed from electrostatic interaction, and sulfamic bonding between the hydrophilic -SO3- groups of SDBS and -NH+= of PANI chains. Hydrogen bonding existed between N and H atoms among PANI chains. The electrostatic interaction and hydrogen bonding immobilized the hydrophilic -SO3- head groups of SDBS around PANI chains, which resulted in the SDBS hydrophobic alkyl chain protruding. These results aid our understanding of the formation of superhydrophobic PANI/SDBS composites, and the design of superhydrophobic materials.