標題: | Controlled Sol-Gel and Diversiform Nanostructure Transitions by Photoresponsive Molecular Switching of Tetraphenylethene- and Azobenzene-Functionalized Organogelators |
作者: | Arumugaperumal, Reguram Hua, Wei-Ling Raghunath, Putikam Lin, Ming-Chang Chung, Wen-Sheng 應用化學系 Department of Applied Chemistry |
關鍵字: | tetraphenylethene-based [2]rotaxanes;calix[4]arene;photoresponsive;supergelators;sol-gel transitions;diversiform structures |
公開日期: | 1-七月-2020 |
摘要: | The implementation of stimuli-responsive materials with dynamically controllable features has long been an important objective that challenges chemists in the materials science field. We report here the synthesis and characterization of [2]rotaxanes (R1 and R1-b) with a molecular shuttle and photoresponsive properties. Axles T1 and T1-b were found to be highly efficient and versatile organogelators toward various nonpolar organic solvents, especially p-xylene, with critical gelation concentrations as low as 0.67 and 0.38 w/v %, respectively. The two molecular stations of switchable [2]rotaxanes (R1 and R1-b) can be revealed or concealed by t-butylcalix[4]arene macrocycle, thus inhibiting the gelation processes of the respective axles T1 and T1-b through the control of intermolecular hydrogen-bonding interactions. The sol-gel transition of axles T1 and T1-b could be achieved by the irradiation of UV-visible light, which interconverted between the extended and contracted forms. Interestingly, the morphologies of organogels in p-xylene, including flakes, nanobelts, fibers, and vesicles depending on the molecular structures of axles T1 and T1-b, were induced by UV-visible light irradiation. Further studies revealed that acid-base-controllable and reversible self-assembled nanostructures of these axle molecules were mainly constructed by the interplay of multi-noncovalent interactions, such as intermolecular pi-pi stacking, CH-pi, and intermolecular hydrogen-bonding interactions. Surprisingly, our TPE molecular systems (R1, R1-b, T1, and T1-b) are nonemissive in their aggregated states, suggesting that not only fluorescence resonance energy transfer but also aggregation-caused quenching may have been functioning. Finally, the mechanical strength of these organogels in various solvents was monitored by rheological experiments. |
URI: | http://dx.doi.org/10.1021/acsami.0c06251 http://hdl.handle.net/11536/154858 |
ISSN: | 1944-8244 |
DOI: | 10.1021/acsami.0c06251 |
期刊: | ACS APPLIED MATERIALS & INTERFACES |
Volume: | 12 |
Issue: | 26 |
起始頁: | 29650 |
結束頁: | 29660 |
顯示於類別: | 期刊論文 |