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Surface interaction of quaternary amines with hair
Author(s) -
Beard B. C.,
Hare J.
Publication year - 2002
Publication title -
journal of surfactants and detergents
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.349
H-Index - 48
eISSN - 1558-9293
pISSN - 1097-3958
DOI - 10.1007/s11743-002-0214-0
Subject(s) - chemistry , cationic polymerization , alkyl , ionic bonding , adsorption , molecule , sulfonate , pulmonary surfactant , x ray photoelectron spectroscopy , polymer chemistry , organic chemistry , chemical engineering , ion , sodium , biochemistry , engineering
Surface analysis by X‐ray photoelectron spectroscopy (XPS) has shown specific 1∶1 (ionic) interaction between cationic alkyl quaternary surfactant molecules and the anionic sulfonate groups present on the hair surface. The primary driving force for the adsorption of alkyl quaternary amine molecules to the surface of the hair from aqueous solution is the ionic interaction between quaternary groups and the surface SO 3 − on the hair. Cationic quaternary molecules incorporating ester and alcohol functionalities (ester quats) demonstrate a lower number of surface quaternary nitrogens per sulfonate group, indicating an altered surface interaction mechanism. For the ester quats, a combination of electrostatic interaction modes exists in addition to the ionic N + /SO 3 − interaction, specifically, H‐bonding interactions of the −C−O, −C−OH, and −C(O)O− polar groups with SO 3 − and other polar groups on the hair. Surface coverage of the ester quat is not reduced despite the decrease in ionic interaction at the surface. Both types of molecules orient their alkyl tails toward the surface. Molecular dynamics modeling of the surfactant/hair surface interaction indicates higher adsorption energies due to increased dipolar interactions for ester quat molecules.