Surfactant adsorption by total internal reflection Raman spectroscopy. Part III: Adsorption onto cellulose

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Physicochemical and engineering aspects, 2011-11, Vol.391 (1), p.10-18
• Main Authors: Woods, David A., Petkov, Jordan, Bain, Colin D.
• Format: Article
• Language: English
• Subjects: Adsorption; Cellulose; colloids; Deposition; hydrolysis; hydrophilicity; hysteresis; Isotherms; octoxynol; Raman spectroscopy; silica; Silicon dioxide; sorption isotherms; Surface chemistry; Surfactant adsorption; Surfactants; Total internal reflection Raman
• ISSN: 0927-7757; 1873-4359
• DOI: 10.1016/j.colsurfa.2011.07.027

[Display omitted] ► Adsorption isotherms of CTAB and Triton X-100 on hydrophilic cellulose are recorded by TIR-Raman scattering. ► Hydrolysis of a trimethylsilyl cellulose surface follows a two-step process. ► CTAB and Triton X-100 do not interact strongly when co-adsorbed on cellulose. TIR Raman spectroscopy has been used to study the adsorption of surfactants onto cellulose. The cellulose was prepared by Langmuir–Blodgett deposition of trimethylsilylcellulose onto silica followed by removal of the trimethylsilyl groups with acid to generate a hydrophilic surface. The reaction was followed in situ with Raman spectroscopy, revealing a two-step hydrolysis. Adsorption isotherms of hexadecyltrimethylammonium bromide (CTAB) and Triton X-100 (TX-100) on hydrophilic cellulose were obtained by TIR Raman scattering under quasi-equilibrium conditions where the bulk concentration was slowly but continuously varied. The isotherms of both surfactants are almost linear, in contrast to the isotherms on hydrophilic silica. The CTAB isotherm shows hysteresis depending on whether the concentration of the surfactant is increasing or decreasing due to a slow adsorption region. A mixture of TX-100 and CTAB shows ideal adsorption, in contrast to adsorption of the same mixture on silica where there is a strong cooperative interaction at low CTAB surface coverage.