Automated photo-aligned liquid crystal elastomer film fabrication with a low-tech, home-built robotic workstation

Abstract

Laboratory procedures are often considered so unique that automating them is not economically justified – time and resources invested in designing, building and calibrating the machines are unlikely to pay off. This is particularly true if cheap labour force (technicians or students) is available. Yet, with increasing availability and dropping prices of many off-the-shelf components such as motorised stages, grippers, light sources (LEDs and lasers), detectors (high resolution, fast cameras), as well as user-friendly programmable microprocessors, many of the repeatable tasks may soon be within reach of either custom-built or universal lab robots. Building on our previous work on fabrication, characterization and applications of light-responsive liquid crystal elastomers (LCEs) in micro-robotics and micro-mechanics, in this paper we present a robotic workstation that can make LCE films with arbitrary molecular orientation. Based on a commercial 3D printer, the RoboLEC (Robot for LCE fabrication) performs precision component handling, structured light illumination, liquid dispensing and UV-triggered polymerization, within a four-hour-long procedure. Thus fabricated films with patterned molecular orientation are compared to the same, but handmade, structures.

Unrestricted Chiral Patterning by Laser Writing in Liquid Crystalline and Plasmonic Nanocomposite Thin Films

“…Light-directed techniques have been demonstrated as highly efficient and versatile methods of structuring organic films via photoalignment, [38,39] photocrosslinking, [40,41] and photothermal patterning. [42][43][44] Light patterning of LC materials exhibiting the Weigert effect [45][46][47] was shown to vertically orient helical nanofilaments, leading to domains showing selective reflection, as demonstrated by Park et al [31] By using masks when illuminating the films, it was possible to prepare patterns of the reflective domains, ultimately leading to a diffraction grating showing wavelength-dependent diffraction with rotated polarization states.…”

“…Light‐directed techniques have been demonstrated as highly efficient and versatile methods of structuring organic films via photoalignment, [ 38,39 ] photocrosslinking, [ 40,41 ] and photothermal patterning. [ 42–44 ] Light patterning of LC materials exhibiting the Weigert effect [ 45–47 ] was shown to vertically orient helical nanofilaments, leading to domains showing selective reflection, as demonstrated by Park et al.…”