Abstract
In the search for novel smart multifunctional liquid crystalline materials, we report the synthesis, thermal and structural characterisation, and the conductivity, of a set of new block and statistical copolymers, containing light-responsive mesogenic groups (MeOAzB), polar sulfonic acids (AMPS), and methyl(methacrylate) groups (MMA). By using a cascade of reversible addition-fragmentation chain polymerisations, RAFT, we have tailored different side-chain polymeric structures by controlling monomer composition (MeOAzB/AMPS/MMA) and configuration. We have yielded simultaneous liquid crystalline behaviour and appreciable conductivity in polymers with low concentrations of polar acid groups, by the formation of smectic phases in narrow aggregates. The light-responsiveness of the polymers, via reversible trans-to-cis photoisomerization of azobenzene groups, and the local activation of conductivity at relatively low temperatures, opens the possibility to prepare polymer electrolytes for energy conversion and storage, whose conductivity could be controlled and optimised by external stimuli, including light irradiation.
Highlights
Liquid crystals, LCs, are fascinating materials that exhibit intermediate states of molecular order between isotropic liquids and crystalline solids, and continue to attract the interest of researchers and industrialists. [1,2] Through the formation of mesophases, liquid crystals combine molecular mobility and long-range order, and their anisotropic properties can be tuned by the application of external fields.Liquid crystals were discovered by Reinitzer at the end of the XIX century [3], and a great variety of liquid crystalline materials exist nowadays, nurturing the development of basic sciences and applied technologies [4]
Our current results suggest that the liquid crystal range is when the mesogenic azobenzenes (MeOAzB) units are included as segments of PMeOAzB25 -b-PAMPS12 (PA-b-PS) and PA-b-PS-b-PM, with a slight increase maintained when the MeOAzB units are included as segments of PA-b-PS and PA-b-PS-b-PM, with in liquid crystal stability (TLCI ~ 139 ◦ C), accompanied with a rigidising effect on the polymer chain a slight increase in liquid crystal stability (TLCI ~ 139 °C), accompanied with a rigidising effect on the (Tg ~ 78 ◦ C)
We have indicated in the PA-b-PS-b-PM curve the underlying d3 spacing associated to the correspond to the diffractogram intensity, a.u.; and curves been shifted arbitrarily along this axis
Summary
LCs, are fascinating materials that exhibit intermediate states of molecular order between isotropic liquids and crystalline solids, and continue to attract the interest of researchers and industrialists. [1,2] Through the formation of mesophases, liquid crystals combine molecular mobility and long-range order, and their anisotropic properties can be tuned by the application of external fields.Liquid crystals were discovered by Reinitzer at the end of the XIX century [3], and a great variety of liquid crystalline materials exist nowadays, nurturing the development of basic sciences and applied technologies [4]. The advance in covalent synthesis and supramolecular assembly techniques (such as, hydrogen-bonding [7] or ionic interactions) have promoted the proliferation of a variety of molecular structures to show liquid crystallinity, very often inspired in complex motives already existing in nature [8]. These include, calamitic and discotic, and bent-core, dimeric, cholesteric, oligomeric, and polymeric materials, as well as crosslinked networks.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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 call
