Synthesis of fluorinated ceramic Janus particles via a Pickering emulsion method

Abstract

HypothesisDispersion or aggregation of ceramic nanoparticles in suspension is mainly influenced by their surface properties. The preparation of hydrophobic/hydrophilic nanoparticles was studied by synthesizing for the first time fluorinated Janus particles via a Pickering emulsion method. ExperimentsFluorinated silica Janus particles were synthesized with a “grafting to” method using silica/wax emulsions. The parameters investigated to control the emulsion were (i) the SiO2 particles/wax ratio, (ii) the cetyltrimethylammonium bromide (CTAB)/SiO2 ratio and (iii) the ionic strength, i.e. NaCl concentration. Prior to grafting with fluorinated molecules, the partially wax-embedded silica particles were functionalized with an aminosilane. Fourier Transformed Infrared and Nuclear Magnetic Resonance spectroscopies, thermogravimetric and zeta potential analyzes were conducted to characterize the fluorinated Janus particles. FindingsSilica quantity has an influence on the silica nanoparticles distribution at the surface of the wax solid droplets. CTAB amount controls the size and shape of silica/wax solid droplets, whereas the ionic strength in the range 0–6.22gL−1 does not influence the silica/wax emulsion. Aminosilane functionalization was successfully employed on partially wax-embedded silica particles, followed by a grafting step with a carboxylic acid fluorinated compound.