The Chemlife research has opened up new avenues in responsive micro-systems, as the principles described herein can be applied to a wide range of polymer formulations (including stimuli-responsive hydrogels) and structural designs. Additionally we have demonstrated a suite of novel examples of smart droplets (micro-vehicles) which achieve autonomous and/or externally controlled movement through the use of stimuli-responsive molecules to “fuel” actuation.
Highlighted results and their exploitation and dissemination:
1. Two-Photon Polymerization of Sugar Responsive 4D Microstructures, A. Ennis, D. Nicdao, S. Kolagatla, L. Dowling, Y. Tskhe, A.J. Thompson, D. Trimble, C. Delaney, L. Florea, Advanced Functional Materials, 2023, DOI: 10.1002/adfm.202213947.
This work represents the first example of sugar-responsive micro-structures fabricated by two-photon polymerisation (2PP). This offers a remarkable solution for achieving fast response hydrogel systems that have been often hindered by the volume-dependent diffusion times of analytes to receptor sites. Moreover, microstructures with programmable actuation (i.e. bending and opening) are fabricated, showcasing the flexibility of 2PP for sophisticated and chemo-responsive 3D hydrogel actuators.
2. Direct Laser Writing of Four-Dimensional Structural Color Microactuators Using a Photonic Photoresist, M. Del Pozo, C. Delaney, C. Bastiaansen, D. Diamond, A. PHJ Schenning, L. Florea, ACS Nano 2020, 14 (8), 9832.
In this publication, the ability to nanostructure cholesteric liquid crystals, while maintaining molecular alignment was demonstrated. This is a watershed case for high-resolution structuring of functional soft polymers.
3. Microstructures for Stimuli Responsive Labels with Multi‐Level Encryption, S. Donato, S. Nocentini, D. Martella, S. Kolagatla, D. S. Wiersma, C. Parmeggiani, C. Delaney, L. Florea*, Small 2024, 20 (20), 2306802.
In this study, the fabrication of free-standing microstructures based on liquid crystalline networks was demonstrated as graphical units of a smart tag for simple physical and optical encryption. Using an array of identical pixels, information was hidden from the observer and revealed only upon application of a specific stimulus. The reading mechanism developed is based on the shape-change of each pixel under stimuli and their colour, that combine together in a two-level encryption label. Once the stimulus was removed, the pixels recovered their original shape and the message remained completely hidden. In essence, this represents an opto-mechanical equivalent of an “invisible ink”. This new concept paves the way for introducing enhanced functionalities in smart micro-systems within a single lithography step, spanning from storage devices with physical encryption to complex motion actuators.
4. Co-organisation of MRS workshop entitled Novel Frontiers in 3D and 4D Multi-Photon Micro-Fabrication Materials, Methods and Applications (May 2022, MRS 2022 Honolulu, Hawaii). This workshop brought together experts in the field. Chemlife achievements were highlighted, through various presentations by the PI and the Chemlife team.
