Gels are viscoelastic solid-like materials comprised of an elastic cross-linked network and a solvent, where the solvent is entrapped and adhered on the large surface area of the solid 3D matrix by physical or chemical forces.1 Their structural softness together with the orderliness at the molecular level provide immense potential for gel mediated applications such as light energy harvesting, molecular recognition, and chiral transcription.2 In addition, gel systems can act as reaction medium and building block of superstructures like porous silica with different chirality and porosity.2 The advent of multistimuli responsive gels with faster and smarter responsive abilities to a variety of external stimuli such as photo, redox reagent, pH, chemical entities have resulted in the utilization of gels for a large number of sensing applications.3 In this context, it is worth mentioning the role of fluorescent gels, with high porous entangled fibre network and multiple active sites, as sensors due to their high sensitivity and fast response time.4 Many organogelators with aggregation induced emission (AIE) luminogens such as tetraphenylethene (TPE), silole and cyanostilbene derivatives, carbazole, oxadiazole etc. as core structure, exhibit “turn-on” or “light up” fluorescent sensing.5 We plan to take the advantages of AIE for sensing purpose by designing gelator systems with AIE active units and plan to utilize them for sensing various analytes. Furthermore, we are planning to synthesize gel based AIEgens with emission at long wavelength which are more biocompatible as sensors in biomedical field. The seminar will provide general introduction of fluorescent gels and their applications in the field of sensing, as well as present the research proposal, along with the initial results based on the study of acridine based polyaryl ether dendron as a dual sensor for trifluoroacetic acid and fluoride ions.

References:
1. Neralagatta M. Sangeetha and Uday Maitra; Supramolecular gels: Functions and uses. Chem. Soc. Rev., 2005, 34, 821–836
2. Dawn A., Shiraki T., Haraguchi , Tamaru S., and Shinkai S. What kind of “soft materials” can we design from molecular gels? Chem. Asian J. 2011, 6, 266 – 282
3. Zhifang S, Qiyu H., Ting H., Zhengyuan L., Yi Z. and Lunzhao Y. Multistimuli-responsive supramolecular gels: design rationale, recent advances, and perspectives. ChemPhysChem.2014, 15, 2421 – 2430.
4. Sang H. P., Nahyun K., Jee H. L., Juyoung Y., Injae S. Synthetic ratiometric fluorescent probes for detection of ions. Chem. Soc. Rev., 2020, 49, 143—179
5. Zujin. Z, Jacky W. Y., Ben Z. T., Self-assembly of organic luminophores with gelation-enhanced emission characteristics, Soft Matter, 2013, 9, 4564–4579