Abstract
The paper describes novel chiral viscoelastic liquid crystalline mixtures and their application for the detection of small rotational displacements of two plates confining cholesteric liquid crystals (CLC). The mixtures are characterized by extremely high viscosities and stability of the selective reflection band (SRB) at ambient temperatures. Even a small rotation applied to the chiral liquid crystal (CLC) cell results in dramatic changes of the reflective properties of sandwiched CLC films. The angle and direction of rotation as well as the magnitude of CLC's shear deformation can be determined for a variety of experimental geometries, each of which is characterized by its own response function. The proposed model explains changes in the reflection spectra for different experimental geometries and relates them to the angle of rotation and magnitude of shear. The method was tested for a detection of small rotations from a distance of up to 50 m and allows for resolving small rotations of the order of fractions of degrees.
Highlights
The method is based on the visualization of the displacement by a specially designed composition of viscoelastic cholesteric liquid crystals (CLCs) that are used as a component of passive autonomous sensor changing reflection and color under applied deformation
The CLCs discussed here were obtained by mixing cyclic oligomers able to form glassy state at room temperature and low molar mass compounds based on cholesterol derivatives
Novel viscoelastic cholesteric mixtures were developed and used to detect and analyze rotation and rotational displacements related to the rotation of two glass or plastic plates with sandwiched CLC sample
Summary
Non-destructive distant detection and testing of deformations are becoming more and more important for a variety of applications ranging from large engineering projects[1] to detection of small nanometer scale deformations in micromechanical devices.[2,6,7,8] Over the last decades numerous optical methods have been developed to quantify stress and deformations.[1,2,3,4,5,6,7,8] The advantages of optical techniques over conventional methods employing electrical sensors are that they do not require any electric power at the point of the deformation measurement, in this sense they are passive. The method is based on the visualization of the displacement by a specially designed composition of viscoelastic cholesteric liquid crystals (CLCs) that are used as a component of passive autonomous sensor changing reflection and color under applied deformation.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
