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China Surfactant Detergent & Cosmetics ›› 2021, Vol. 51 ›› Issue (8): 725-733.doi: 10.3969/j.issn.1001-1803.2021.08.005

• Development and application • Previous Articles     Next Articles

Adsorption behaviors of didecyl quaternary ammonium salts with different counterions on polytetrafluoroethylene surface

Zhi Lifei(),Shi Xiufang,Zhang Erzhuang,Li Xiaoming,Wang Hui,Pan Ruili   

  1. College of Chemistry and Biological Engineering, Taiyuan University of Science and Technology, Taiyuan, Shanxi 030024, China
  • Received:2021-03-22 Revised:2021-07-20 Online:2021-08-22 Published:2021-08-24
  • Contact: Lifei Zhi E-mail:lifeizhi@yeah.net

Abstract:

The sessile drop method was used to study the adsorption behaviors of a series of didecyl quaternary ammonium salts with different counterions and a Gemini quaternary ammonium salt on the surface of superhydrophobic material polytetrafluoroethylene (PTFE). The effects of the surface activity, type and concentration of surfactants on the contact angle were investigated, and the changes of spreading coefficient, adhesion tension and adhesion work were discussed. The results show that the contact angle of didecyl quaternary ammonium salts on the surface of PTFE shows a trend of first decreasing and then increasing with the increase of size of counterions. Among them, didecyldimethylammonium valerate (DDAV) which has the largest counterion shows the best wetting on the surface of PTFE; the spreading coefficient (S) is decreased first and then increased with the increase of counterion size; when the concentration of the surfactant is lower than cmc, there is a good linear relationship between adhesion and surface tension; when the concentration is larger than the cmc, the solution of the surfactant with small counterion forms a saturated adsorption layer at the solid-liquid interface and the gas-liquid interface. Surfactants with larger counterions reach saturation adsorption at the gas-liquid interface, but do not reach saturation at the solid-liquid interface. Their adsorption continues and the wetting performance is enhanced with the increase of concentration. Therefore, the influences of a series of didecyl quaternary ammonium salts on the surface of PTFE were obtained, and the adsorption model was established, which provided a theoretical basis for further understanding of the adsorption of such surfactants on the surface of hydrophobic materials, and facilitated the application of such surfactants.

Key words: quaternary ammonium salt, surfactant, adsorption, wetting, contact angle

CLC Number: 

  • TQ423