Analysis of gratings induced in azo-dye doped liquid crystals

Frey, Laurent; Kaczmarek, M.; Jonathan, J.M.C.; Roosen, Gérald

doi:10.1016/s0925-3467(01)00139-2

Cited by 25 publications

(2 citation statements)

References 13 publications

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“…4,5,[7][8][9]22 In tendons, collagen fibers and their bundles do not follow a strictly parallel path along the tendon axis, but rather show a helical arrangement that obeys the rules of supramolecular chemistry. [12][13][14][15][16] The resulting superstructure is similar to a twisted grain boundary liquid crystal, 13 and the variations in fiber direction in the tissue section are reflected in the absorbances, DR values, and respective standard deviations.…”

Section: Ponceau Ss-collagen Complexes and Liquid Crystalsmentioning

confidence: 99%

Supramolecular order following binding of the dichroic birefringent sulfonic dye Ponceau SS to collagen fibers

Vidal¹,

Mello²

2005

Biopolymers

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The optical anisotropies (linear dichroism or LD and birefringence) of crystalline aggregates of the sulfonic azo-dye Ponceau SS and of dye complexed with chicken tendon collagen fibers were investigated in order to assess their polarizing properties and similarity to liquid crystals. In some experiments, the staining was preceded by treatment with picric acid. Crystalline fibrous aggregates of the dye had a negative LD, and their electronic transitions were oriented perpendicular to the filamentary structures. The binding of Ponceau SS molecules to the collagen fibers altered the LD signal, with variations in the fiber orientation affecting the resulting dichroic ratios. The long axis of the rod-like dye molecule was assumed to be bound in register, parallel to the collagen fiber. Picric acid did not affect the oriented binding of the azo dye to collagen fibers. There were differences in the optical anisotropy of Ponceau SS-stained tendons from 21-day-old and 41-day-old chickens, indicating that Ponceau SS was able to distinguish between different ordered states of macromolecular aggregation in chicken tendon collagen fibers. In the presence of dichroic rod-like azo-dye molecules such as Ponceau SS, collagen also formed structures with a much higher degree of orientation. The presence of LD in the Ponceau SS-collagen complex even in unpolarized light indicated that this complex can act as a polarizer.

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Section: Ponceau Ss-collagen Complexes and Liquid Crystalsmentioning

confidence: 99%

Supramolecular order following binding of the dichroic birefringent sulfonic dye Ponceau SS to collagen fibers

Vidal¹,

Mello²

2005

Biopolymers

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“…MR doped nematic films are characterized by advanced photo-charge and DC space charge field generation efficiency, and this material is perhaps the most non-linear optical material ever known. Such extraordinarily large non-linearity enables the performance of several alloptical switching, limiting, image modulation, and sensing processes at unprecedentedly low threshold powers [9][10][11]. Photorefractive-like reorientation is another mechanism in which photo-excited dopants bring about the formation of space-charge complexes, and their induced fields force the molecules to reorient by enhancing the photoconductivity.…”

Section: Introductionmentioning

confidence: 99%