Association and adsorption of nonionic flexible chain surfactants

Journal Article · Sat Sep 01 04:00:00 EDT 1990 · Langmuir; (USA)

DOI:https://doi.org/10.1021/la00099a008· OSTI ID:6332359

Boehmer, M R; Koopal, L K ^[1]

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1. Wageningen Agricultural Univ. (Netherlands)

An extension of the self-consistent-field theory for chain molecules of Scheutjens and Fleer is used to study the micellization of nonionic surfactants and their adsorption from aqueous solution on hydrophilic and hydrophobic surfaces. The theory predicts that the critical micelle concentration increases and the aggregation number decreases if the hydrophilic block becomes longer. This is in agreement with experimental findings. On hydrophilic surfaces, where the chains adhere with their hydrophilic segments to the surface, the affinity increases with the hydrophilic chain length. The adsorption isotherm reaches a plateau value at the cmc. At constant hydrophobic block length, the plateau adsorption decreases with increasing length of the hydrophilic block. If the ratio between the number of hydrophobic and hydrophilic segments is around one, strong cooperative adsorption and the formation of a surfactant bilayer are predicted. On a hydrophobic surface the hydrophobic segments adhere to the surface, and for all chain lengths studied a monolayer of surfactant is predicted. Also in this case, the plateau adsorption decreases with increasing length of the hydrophilic chain. The results agree well with experimental results for both types of surfaces.

• OSTI ID: 6332359
• Journal Information: Langmuir; (USA), Journal Name: Langmuir; (USA) Vol. 6:9; ISSN 0743-7463; ISSN LANGD
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ADSORPTION ISOTHERMS
AQUEOUS SOLUTIONS
CALCULATION METHODS
DISPERSIONS
ISOTHERMS
MICELLAR SYSTEMS
MIXTURES
PHYSICAL PROPERTIES
SELF-CONSISTENT FIELD
SOLUTIONS
SURFACTANTS
THERMODYNAMIC PROPERTIES