Origin of the In-Plane Anisotropy in Langmuir-Blodgett Films

Langmuir–Blodgett films of cellulose nanocrystals: Preparation and characterization

“…Whatever the case, the same kind of organization has been observed in Langmuir-Blodgett films, with rod-like particles or polymers such as DNA [30,31], polyglutamate [32][33][34], polysiloxane [35,36], alkylated cellulose [37], and discotic crystals [38]. In some instances, the organization of the films occurs during the compression process on the subphase [39,40], in others cases, it was reported during the deposition process of monolayers [41][42][43][44]. In the case of the cellulose nanocrystals used in this work, the stretching during the dipping process is very likely evidenced by the general organization of the films.…”

Infrared spectroscopic study on the Langmuir–Blodgett films of merocyanine dye–arachidic acid–n-octadecane ternary system

“…4,5 The absorption peak is markedly redshifted from that of the monomer band ͑540 nm͒, showing the characteristics of J band associated with a chromophore alignment of head-to-tail type which is often referred to as the J aggregate. 4,5 Although a blueshifted band is expected for an H aggregate or a chromophore alignment of side-by-side type, there have been only a few reports as to the occurrence of blueshifted bands in the MS-containing films until the mid 1990's, while the J aggregates in the MS-containing LB films have been intensively studied for the past two decades or more. Nakahara et al 6 have observed a pronounced blueshifted band in the floating monolayers of the MS-methyl arachidate-n-hexadecane ternary system.…”

“…7͒ in the mixed LB film of the ternary system with the molar mixing ratio ͓MS͔:͓C 20 -d͔:͓AL 18 -d(or AL 18 )͔ ϭ1:2:x (xϭ1, 2,3,4,5), and the AL 18 -d molecules would hinder the motion of the hydrocarbon chain of MS by the van der Waals interaction among the saturated hydrocarbon chains. 18 This is based on the facts revealed in Sec.…”

“…I, it is known that the LB film of the MS-C 20 binary system shows the redshifted band at 590 nm associated with the J aggregate, 4,5 and that a blueshifted band at 505 nm is observed for the mixed LB films of the MS-C 20 -AL 18 ternary system with the molar mixing ratio ͓MS͔:͓C 20 ͔:͓AL 18 ͔ϭ1:2:x (xϭ0.5, 1.0, and 1.5͒. [7][8][9][10] We have concluded that the 505 nm band is due to the H aggregates.…”

Influence of heat treatment in air, and subsequent hydrothermal treatment in the liquid phase or water treatment in the liquid phase on a mixed Langmuir–Blodgett film of merocyanine dye-arachidic acid-n-octadecane ternary system

“…1) [5][6][7][8][9]. The J-and H-aggregates can be easily controlled in as-deposited LB films of MS 18 [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19], and the former and latter formation mechanisms have been so far elucidated by and our group [6], respectively. Recently, we have attempted conversions from the red-shifted J-to blue-shifted aggregates [7], and from the blue-shifted H-to redshifted aggregates [8] using the perturbation because of the investigation into the possibility of controlling dye aggregation states, and the confirmation of dye alignments of J- [13][14][15] and H-aggregates [6] clarified in the MS 18 LB films.…”