Thiol–acrylate side-chain liquid crystal elastomers. Issue 25 (17th June 2022)

• Record Type: Journal Article
• Authors: Guo, Hongye; Saed, Mohand O.; Terentjev, Eugene M.
• Is Part Of: Soft matter. Volume 18:Issue 25(2022)
• Page Start: 4803
• Page End: 4809
• Publication Date: 2022-06-17
• Subjects: Soft condensed matter -- Periodicals; 530.413
• DOI: 10.1039/d2sm00547f
• Languages: English
• ISSNs: 1744-683X

Abstract

Abstract : The Michael addition 'click' chemistry was used to graft acrylate-terminated mesogenic groups onto the polysiloxane backbone polymer chain with thiol functional groups, with a constant 15% fraction of diacrylate reacting monomers as crosslinkers. Abstract : The Michael addition 'click' chemistry was used to graft acrylate-terminated mesogenic groups onto the polysiloxane backbone polymer chain with thiol functional groups, with a constant 15% fraction of diacrylate reacting monomers as crosslinkers. Three different types of mesogens were used, and also their 50 : 50 mixtures, and in all cases we have obtained the smectic-A phase of the resulting liquid crystalline elastomer. Using X-ray diffraction, calorimetry and dynamic mechanical analysis, we investigated the relationship between the molecular structure of mesogenic side groups and the structure and properties of the elastomers. The shape-memory of smectic elastomers was verified. The unusual features were the semi-crystalline nature of elastomers with non-polar mesogens and the clear role of side-by-side rod dimerization of polar mesogens leading to a higher smectic layer spacing. We investigated the evolution of the smectic alignment on uniaxial stretching along the layer normal and identified two distinct ways in which the elastomer responds: the coarsened Helfrich–Hurault zig-zag layer texture and the large-scale stripe domains of uniform layer rotation in the systems with lower order parameter and the associated layer constraints.