Yang Fei, Liu Shangying, Xu Jian, Lan Qiang, Wei Fang, Sun Dejun
Key Laboratory for Colloid & Interface Chemistry of Education Ministry, Shandong University, Jinan, Shandong 250100, People's Republic of China.
J Colloid Interface Sci. 2006 Oct 1;302(1):159-69. doi: 10.1016/j.jcis.2006.06.015. Epub 2006 Jun 20.
The formation and stability of liquid paraffin-in-water emulsions stabilized solely by positively charged plate-like layered double hydroxides (LDHs) particles were described here. The effects of adding salt into LDHs dispersions on particle zeta potential, particle contact angle, particle adsorption at the oil-water interface and the structure strength of dispersions were studied. It was found that the zeta potential of particles gradually decreased with the increase of salt concentration, but the variation of contact angle with salt concentration was very small. The adsorption of particles at the oil-water interface occurred due to the reduction of particle zeta potential. The structural strength of LDHs dispersions was strengthened with the increase of salt and particle concentrations. The effects of particle concentration, salt concentration and oil phase volume fraction on the formation, stability and type of emulsions were investigated and discussed in relation to the adsorption of particles at the oil-water interface and the structural strength of LDHs dispersions. Finally, the possible stabilization mechanisms of emulsions were put forward: the decrease of particle zeta potential leads to particle adsorption at the oil-water interface and the formation of a network of particles at the interface, both of which are crucial for emulsion formation and stability; the structural strength of LDHs dispersions is responsible for emulsion stability, but is not necessary for emulsion formation.
本文描述了仅由带正电荷的片状层状双氢氧化物（LDHs）颗粒稳定的水包液状石蜡乳液的形成和稳定性。研究了向LDHs分散体中添加盐对颗粒zeta电位、颗粒接触角、颗粒在油水界面的吸附以及分散体结构强度的影响。结果发现，随着盐浓度的增加，颗粒的zeta电位逐渐降低，但接触角随盐浓度的变化很小。颗粒在油水界面的吸附是由于颗粒zeta电位的降低而发生的。LDHs分散体的结构强度随着盐和颗粒浓度的增加而增强。研究并讨论了颗粒浓度、盐浓度和油相体积分数对乳液形成、稳定性和类型的影响，并将其与颗粒在油水界面的吸附以及LDHs分散体的结构强度相关联。最后，提出了乳液可能的稳定机制：颗粒zeta电位的降低导致颗粒在油水界面的吸附以及界面处颗粒网络的形成，这两者对于乳液的形成和稳定性都至关重要；LDHs分散体的结构强度负责乳液的稳定性，但对于乳液的形成并非必需。
