The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/macp.201800318.
AzopolymersA series of side-chain polymers with a bifunctional repeating unit are prepared by post-polymerization functionalization of poly(propargyl methacrylate) (PPMA) with several azides derived from bis(hydroxymethyl) propionic acid (bis-MPA). The azide incorporates one photoresponsive 4-cyanoazobenzene unit and one photoinert promesogenic moiety at each repeating unit. Both the effect of the photoinert (4-cyanobipheynyl vs 4-cyanotolane) and of the linking group (ester vs carbamate) on the liquid crystalline properties and the generation of optical anisotropy, linear or circular birefringences are explored.
The capability to optically control surface structuration of azopolymer films is an important goal in different research fields, enabling remote activation and tuning of associated processes mediated by the surface. In this work, two amorphous azopolymers, structurally engineered in order to exhibit linear and circular photoinduced optical anisotropies, have been investigated, with the aim to design complex light-reconfigurable topographical structures. Different intensity and polarization patterns were generated by two-or four-beams interferometry and inscribed on the polymer films. Relief depths in the range of hundreds of nanometers have been produced, mediated by the bulk photoinduced anisotropies of the materials. It is shown that, on the basis of the kind of light patterns (intensity and/or polarization), depth and shape of the relief grating can be tuned. Polymers with higher photoinduced birefringences enable one to produce deeper reliefs. Bidimensional light polarization patterns generate complex surface structures, even with chiral features, envisaging the possibility to engineer large area opto-controllable surfaces and platforms.
In the search to obtain new and more efficient components of memory devices, we report the photochromic, dielectric and electrochemical response of a light-responsive organic compound, and its memory performance under electrical fields. The so-called N(1)-[12-(4-(4'-isobutyloxyphenyldiazo)phenoxy)dodecyloxy)]thymine, tAZOi, molecule contains one azobenzene group, which provides with photochromic character, and one terminal thymine group, capable to form hydrogen bonds and assemble supramolecular dimers, (tAZOi)2. We have calculated the optical absorption coefficient, extinction coefficient and refractive index of tAZOi, which obeys the single oscillator Wemple-DiDomenico model. An ITO/tAZOi/Al device has been prepared and presents two switchable conductance states with preservation of memory performance. The mechanism linked to the resistive randomaccess memory (RRAM) has been evaluated by molecular modelling and is controlled by ptype conduction, possibly involving hydrogen-bonding. Upon UV irradiation at ~365 nm, tAZOi displays an increase in the complex permittivity driven by trans-to-cis
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