The liquid–vapour transition in monolayers of n-pentadecanoic acid at the air/water interface

Phases and phase transitions in Gibbs monolayers of an alkyl phosphate surfactant

“…PM-IRRAS spectra of the monolayers of 6.0 × 10 −5 M n-TDP at 10 • C after equilibrium is attained also show similar bands as found for the bright monolayer phase at 5 • C, indicating the condensed nature of the final phase [52]. Since the final phase is a condensed phase and the initial phase is a gas phase, the remaining middle phase will definitely be a LE phase [16][17][18][19]. Thus, the initial transition occurs at 8 • C and at zero surface pressure is a G-LE phase transition, while the latter transition is a LE-LC phase transition [10].…”

“…Comparing with the results for spread monolayers [16][17][18][19], an attempt is made, here, to characterize these phases and phase transitions. During the formation of Gibbs monolayers, the concentration of the surface molecules should be very low just after sweeping of the solution surface by the Teflon barriers.…”

“…In another report, the existence of only a G-LC phase transition is concluded [24]. Although the conditions under which these three phase transitions occur in spread monolayers are detailed [16][17][18][19], such work is still absent for medium-chain water-soluble amphiphiles in Gibbs adsorption layers. The principal aim of this article is to study the details of the conditions for these phase transitions in Gibbs monolayers.…”

“…These are gaseous (G), liquid expanded (LE), liquid condensed (LC), and solid (S) phases. The phase transitions G-LC, G-LE, and LE-LC all are of first order [17][18][19]. The G-LE phase transition occurs at very low pressure, whereas the LE-LC phase transition takes place at relatively high surface pressure.…”

How many phases and phase transitions do exist in Gibbs adsorption layers at the air–water interface?

“…The general phase diagram of a water-insoluble amphiphile in spread or Langmuir monolayers consists of four phases, which are gas (G), liquid expanded (LE), liquid condensed (LC) and solid (S) phases [1][2][3][4]. Besides these general phases, at least seven different LC phases (known as mesophase) have been found to exist in these monolayers [1][2][3][4][5][6][7][8][9][10][11][12].…”