Nonionic surfactants are mainly silicone-polyether copolymers with polysiloxane backbone as the hydrophobic group and polyether as the hydrophilic group. By changing the type, quantity and position of the introduced polyether, the hydrophilic and lipophilic properties of the non-ionic silicone surfactant can be effectively adjusted to achieve different lubrication, emulsification, foam stabilizing and defoaming properties, and can be widely used in personal applications. Care products. Since ethoxy groups (EO) are negatively charged and can increase the polarity of silicone surfactant molecules, the greater the number of EOs, the more hydrophilic the silicone surfactant molecules are.
Studies by KIM and others have shown that the cmc and γcmc of polyether-modified surfactants increase with the increase of EO chain length. Pan Qiang et al.’s research shows that the surface activity of polyether-modified trisiloxane decreases as the EO chain length increases, while the corresponding polyether-modified tetrasiloxane has an optimal EO chain length (EO = 8). Within a certain range of lower EO numbers, the γcmc changes of both are small. However, after the EO number exceeds a certain range, the γcmc increase is more significant. Regarding the wetting properties, the wetting ability of polyether-modified trisiloxane shows a weakening trend with the increase of EO number, while the polyether-modified tetrasiloxane has little change when the EO chain length is shorter. It weakens significantly only when the chain length is longer.
