Adsorption kinetics of halloysite nanotube and modified halloysite at the Palm oil-water interface and Pickering emulsion stabilized by halloysite nanotube and modified halloysite nanotube

Abstract In this study, the interfacial tension behavior of halloysite nanotube (HNT) as a hydrophilic nanoparticle and modified APTES-HNT as a hydrophobic nanoparticle at the palm oil-water interface was investigated. The result of this study was used to determine the stability and potential formation of Pickering emulsion as a novel dispersed system. The diffusion coefficients at the initial and late stages of adsorption were obtained. The results indicated that the interfacial tension of palm oil-water decreased with increasing the nanoparticles concentration. The diffusion coefficient at the different concentrations (0.1 g/L to 0.5 g/L) for the short time was obtained to be within the range of 1.4480 × 10 - 14 - 6.1408 × 10 - 13 (m 2 /s) and for the longer times was within the range of 4.8065 × 10 - 16 - 7.4476 × 10 - 15  m 2 /s. The results indicated that the HNT and APTES-HNT produced significant surface and interfacial tension reductions, which confirmed their ability for stabilization of Pickering emulsion. The measured contact angle for HNT and APTES-HNT were determined to be 29.14 ° and 97 ° , respectively. Stable oil-in-water and water-in-oil emulsion were obtained for HNT and APTES-HNT, respectively. The emulsions exhibited no coalescence over a period of 4 weeks.