Structures of Collapsed Lipid Monolayers Investigated as Langmuir-Blodgett Films by Atomic Force Microscopy

Langmuir monolayers and Langmuir–Blodgett films of 1-acyl-1,2,4-triazoles

“…After collapse, the Langmuir isotherm of StT-C18 shows a drop of the p value followed by a pseudo-plateau region where the p value increases only slightly. The behavior is explained as destruction and distortion of the monolayer and subsequent formation of a trilayer by a roll-over mechanism as described for stearic acid [29,30]. Upon further compression a second steep increase of the p value occurs followed by the final collapse at a p value of $67 mN m À1 (p fc ) and mmA of 2.5 Å 2 (mmA fc ).…”

“…Furthermore, it is demonstrated that the film collapses after the sharp increase of the surface pressure up to a value of $60 mN m À1 with a clear 'spike' followed by a pseudo-plateau region of slightly increasing p. The 'spike' is interpreted to indicate the buckling and subsequent folding of the monolayer, and the pseudo-plateau is considered to be a region where a trilayer forms by a roll-over mechanism of the previously existent monolayer [29]. This conclusion is based on calculations of mmA of the Langmuir isotherms and on atomic force microscopy (AFM) measurements on the transferred Langmuir-Blodgett films [30]. The roll-over mechanism was firstly proposed by Ries for 2-hydroxytetracosanoic acid whereby weakening, folding and bending of the monolayer occur upon film compression on the water surface [31].…”

Dynamics driven by lipophilic force in Langmuir monolayers: In-plane and out-of-plane growth

“…D uring the form a tion o f m onolayers the com petition betw een the first two forces plays the key role w hile the im portance o f the third grow s as the surface density is increased, as is expected. G row th o f L angm uir m onolayers o f fatty acids w ith the em ergence o f different structural phases at different surface concentrations or surface pressures has been thoroughly studied [21], as has been the dynam ics at very high n values, i.e., collapse [22][23][24][25][26][27]. However, even basic questions regarding the long-term dynam ics o f L angm uir m onolayers at low er "uttam.basak@saha.ac.in talokmay.datta@saha.ac.in surface pressure in the purported "stable" zones, such as the specific differences in dynam ics o f m onolayers that destabil ize through a desorption-dom inated (DD) m echanism from those undergoing a nucleation-dom inated (ND) destabilization have not been addressed, and the m ajor destabilizing force am ong the above three has not been identified.…”

Morphology of compressed dipalmitoyl phosphatidylcholine monolayers investigated by atomic force microscopy

“…Direct evidence of the collapse process of a monolayer comes from the observation of its microstructures [4,7,8,[14][15][16][17][18][19][20][21][22][23][24][25][26]. Long narrow ribbons of collapsing monolayers resulting from fracture process were observed [4,[14][15][16][17].…”

“…Long narrow ribbons of collapsing monolayers resulting from fracture process were observed [4,[14][15][16][17]. Instead of the ribbon-like collapse structure, other morphological studies revealed different collapse structures as well [7,8,[18][19][20][21]. However, there are relatively few direct observations of the collapse microstructures of a DPPC monolayer.…”