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New Features on the Phase Transitions of Behenic Acid Monolayers as Unveiled by 2D‐Compressibility Coefficient
Author(s) -
GAO WenYing,
YU ZhiWu
Publication year - 2008
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.200890288
Subject(s) - compressibility , behenic acid , chemistry , monolayer , phase transition , phase (matter) , compression (physics) , langmuir , type (biology) , thermodynamics , equation of state , crystallography , organic chemistry , physics , adsorption , ecology , biochemistry , fatty acid , palmitic acid , biology
Phase behavior of Langmuir monolayers of behenic acid (BeA) has been examined by two‐dimensional compressibility. It was found that phase transitions of BeA could be classified into two distinct categories, named Type‐I and Type‐II in this work. The former is typified by a positive peak on the compressibility‐pressure ( β ‐) curve, indicating the transition can occur itself in a way of collapse from the initial structure. The latter is characterized by a dropping step on the β ‐ curve, implying that it cannot happen itself and the driven force is continuous compression. For BeA molecules, compressibility coefficients at the initial and final state are the same, β i = β f , for Type‐I phase transition from L 2 to L 2 ' state, whilst β i > β f for Type‐II phase transition from L 2 ' state to S state.