Liquid crystalline cellulose derivative elastomer films under uniaxial strain

Mesogenic cellulose derivative chains cross-linked into free-standing thin films were prepared by a shear-casting technique from anisotropic precursor solutions of thermotropic (acetoxypropyl)cellulose. After shear cessation a macroscopically oriented serpentine structure with the director in averag...

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Bibliographic Details
Published in:Cellulose (London) 2009-04, Vol.16 (2), p.199-205
Main Authors: Godinho, M. H, Filip, D, Costa, I, Carvalho, A.-L, Figueirinhas, J. L, Terentjev, E. M
Format: Article
Language:English
Subjects:
Anisotropy
Bioorganic Chemistry
Cellulose
Ceramics
Chemistry
Chemistry and Materials Science
Composites
Crosslinking
Crystalline cellulose
Deformation
Elastomers
Glass
Liquid crystals
Mechanical properties
Motion picture directors & producers
Natural Materials
Optical microscopy
Optical properties
Order parameters
Organic Chemistry
Physical Chemistry
Polymer Sciences
Serpentine
Shear
Sustainable Development
Thin films
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Summary:Mesogenic cellulose derivative chains cross-linked into free-standing thin films were prepared by a shear-casting technique from anisotropic precursor solutions of thermotropic (acetoxypropyl)cellulose. After shear cessation a macroscopically oriented serpentine structure with the director in average along the shear direction is locked resulting in anisotropic optical and mechanical properties of the material. These films were submitted to an external uniaxial mechanical field perpendicular and parallel to the shear direction. Stretching perpendicular to the shear direction produced significant director rotations and a reset of order of the director order parameter for a deformation in the range 2-3 as detected by X-rays and optical microscopy. The different response found for strains imposed parallel and perpendicular to the initial average director orientation indicates that even though our system shows a serpentine director modulation that is either attenuated or reinforced by deformations parallel or perpendicular to the shear direction, its behaviour is similar to theoretical predictions for monodomain nematic elastomers described in the literature.
ISSN:0969-0239
1572-882X
DOI:10.1007/s10570-008-9258-9