Studies of molecular monolayers at air-liquid interfaces by second harmonic generation: question of orientational phase transition

Conference · Sat Jun 01 04:00:00 EDT 1985

OSTI ID:6174939

Rasing, T; Shen, Y R; Kim, M W; Grubb, S; Bock, J

Insoluble molecular monolayers at gas-liquid interfaces provide an insight to the understanding of surfactants, wetting, microemulsions and membrane structures and offer a possibility to study the rich world of 2-dimensional phase transitions. In the interpretation of the observed properties of these systems various assumptions about the molecular orientation are often made, but so far few clear experimental data exist. In this paper we will show how optical second harmonic generation (SHG) can be used to measure the molecular orientation of monolayers of surfactant molecules at water-air interfaces. By simultaneously measuring the surface pressure versus surface molecular area we can show for the first time that the observed liquid condensed-liquid expanded transition is an orientational phase transition. 7 refs., 4 figs.

• Research Organization: Lawrence Berkeley Lab., CA (USA); Exxon Research and Engineering Co., Annandale, NJ (USA)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6174939
• Report Number(s): LBL-20067; CONF-850605-8; ON: DE86002871
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
640420 -- Fluid Physics-- Properties & Structure of Fluids-- (-1987)
74 ATOMIC AND MOLECULAR PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
FILMS
FREQUENCY MIXING
HARMONIC GENERATION
NONLINEAR OPTICS
OPTICS
ORIENTATION
PHASE TRANSFORMATIONS
SURFACTANTS
THIN FILMS
TWO-DIMENSIONAL CALCULATIONS