A segment of the -helix structure of PBLG (H-atoms not labeled).
Effect of laser illumination on the SA of PBLG. Topographic images obtained by AFM and their corresponding FT patterns, respectively. [(a) and (b)] Without illumination [(c) and (d)] under illumination (15 min, averaged power ); images of separated domains . Double arrows denote polarization direction of the beam. The profile line in Fig. 4(b) is taken along the dashed line in . Deposition corresponds to 80% nominal coverage. Solvent composition: pure toluene; [, , and ] toluene and chloroform (1:1 ratio). Scanned area and range of reciprocal vectors along the axes are specified on each image.
Effect of illumination with Ti:sapphire femtosecond pulses on the SA of PBLG. [ and ] Topographic images obtained by AFM and [ and ] their corresponding FT patterns, respectively. The images were obtained on regions separated by . , 12 min; deposition corresponds to a nominal coverage of 80% with mixture of toluene and chloroform (1:1 ratio).
Solvent composition influences the thickness of the self-assembled film. (a) isotherms of PBLG dissolved in pure toluene (dotted line), pure chloroform (solid line) and their mixture of ratio 1:1 (dashed line). (b) Topography profile of PBLG film along the black dashed line in Fig. 2.
Effect of laser illumination on the SA of alamethicin. (a) Nonilluminated self-assembled film; (b) Illuminated self-assembled film; Nd:YAG laser (, 15 min). Solvent mixture in (a) and (b) was a mixture of toluene and chloroform (with ratio of 1:1) and a deposition corresponded to a nominal coverage of 80%.
Distortions in illuminated self-assembled PBLG films. [ and ] AFM topographic images and [ and ] their corresponding FT patterns. A domain on the same sample of Figs. 2 and 2 which reveals a region with twisting deformation as denoted by the colored arrows and the corresponding colored arcs in its FT image. Nominal deposition of 40% of complete monolayer coverage (, 15 min; a solvent mixture of toluene and chloroform with 1:1 ratio).
Effect of polarization and timing on the SA of PBLG, and “build-up” of layers. Topographic image of a sample illuminated by circularly polarized Nd:YAG pulses (, 15 min) and its corresponding FT pattern . Topographic image of a sample illuminated by Ti:sapphire pulses (, 3 min) after complete evaporation (15 min), and its corresponding FT pattern . Topographic image of a mixture of PBLG and alamethicn (at a ratio that corresponds to an equal coverage by each component), and its corresponding FT pattern . A mixture of toluene and chloroform (1:1 ratio) was used for all the films, and a deposition corresponded to a nominal coverage of 80%.
Rotational diffusion coefficient vs the thickness of the solvent layer for PBLG (lower and middle curves) and alamethicin (upper curve). The two vertical lines on the lower curve denote the concentrations at which isotropic-nematic phase transition occurs (Refs. 17 and 18) The middle horizontal curve corresponds to for infinite dilution.
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