Multilayer deposition of stearic acid—calcium stearate monomolecular films

Ion redistribution and meniscus stability at Langmuir monolayer deposition

“…According to the thermodynamic relation between adhesion work and contact angle [54,55] the equilibrium contact angle should decrease at such conditions. This conclusion is supported by some experimental data for the deposition of fatty acid monolayers in the pH interval 4-7 in the presence and absence of bivalent cations [5][6][7]10,22]. Also at docosylamine monolayers deposition, the static contact angles after withdrawal have a maximum in the same pH interval where the electrostatic free energy of interaction has a minimum [55].…”

“…The receding dynamic contact angle decreases relatively to the static (equilibrium) contact angle as the deposition velocity increases [7,10,12,64,65]. Huh and Scriven [66] considered the hydrodynamics of the steady movement of the contact line over a solid surface with aid of the creeping flow approximation and the lubrication approximation.…”

“…For the Y-type of LB-deposition, at constant withdrawal velocity, a stationary acute (but opaque during dipping) contact angle is usually formed between the substrate surface and the spread monolayer [5][6][7][10][11][12]22,55,63]. The receding dynamic contact angle decreases relatively to the static (equilibrium) contact angle as the deposition velocity increases [7,10,12,64,65].…”

“…The deposition of spread monolayers on the substrate surface is accompanied by complicated processes near the three-phase contact line originated from interactions between the substrate and the monolayer. Molecular interactions and reorganization [4][5][6][7][8][9][10][11], hydrodynamic processes [9,10,[12][13][14][15], energy dissipation due to adsorption and desorption processes [14,15], phase transitions [16][17][18][19], electrostatic interactions [20,21], and monolayer ionization and counterion binding [4][5][6][7][8][9][10][11][22][23][24] are effective between the substrate and the monolayer. These processes influence the dynamic contact angle during the deposition, the monolayer transfer ratio, the adhesion work, the maximum deposition rate as well as composition, structure and morphology of LB films.…”

Film Deposition

“…However, both X-type and Ztype structures could also be obtained by moving the substrate in one direction through the floating monolayer and in the opposite direction through the clean water surface. In some cases, Z-type deposition has been achieved by decompression of the monolayer during the downstroke.<74, 216,217) A number of techniques are now available to accurately measure contact angles and interaction energies during monolayer transfer04, 21,24,28,44,[60][61][62]218); the application of these may well lead to a much better insight into the various LB deposition modes.…”