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Binary mixture of monostearin‐distearin monolayers at the air–water interface
Author(s) -
De la Fuente Feria Julia,
Patino Juan M. Rodríguez
Publication year - 1995
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690410812
Subject(s) - miscibility , monolayer , langmuir , thermodynamics , chemistry , emulsion , molecule , surface pressure , chemical engineering , chromatography , organic chemistry , adsorption , polymer , mechanics , biochemistry , physics , engineering
The study of mixed films has become of considerable interest both from theoretical and practical points of view. The π‐A isotherms of monostearin‐distearin (about 50% 1,3‐ and 50% 1,2‐isomers) mixed films spread on water as a function of emulsifier ratio and temperature were studied in an automated Langmuir‐type film balance. When molecules of both emulsifiers are spread on the air–water interface they are packed more closely together than when either emulsifier is present alone, and they enter into some form of association. This association can be demonstrated by surface pressure‐area isotherms and by thermodynamic studies. The characteristics of the mixed films, their elasticity and miscibility, which are of interest in emulsion or foam stability are discussed. A molecular model established can explain the interactions between film and subphase molecules and their relationships with variables of the process (pressure and temperature). This model fits the calculated thermodynamic parameters.