Exploring electro-droplet assisted polymerization reactions and its relevance in prebiotic chemistry

Guha, Mainak (2025) Exploring electro-droplet assisted polymerization reactions and its relevance in prebiotic chemistry. Masters thesis, Indian Institute of Science Education and Research Kolkata.

Text (MS Dissertation of Mainak Guha (23MP028)) 23MP028_Thesis_file.pdf - Submitted Version Restricted to Repository staff only Download (1MB)

Abstract

Origin of life is an open question, pursuit of which has yielded many facts and even more speculations. Among the hypotheses about the origin of life, RNA-world hypothesis, protein interaction-world hypothesis and lipid-world hypothesis, the last one emphasizes the importance of compartmentalization in the harsh prebiotic environment to protect small molecules from degradation, increase effective molarity to accelerate reactions, solubilize starting materials to facilitate reactions of organic molecules in water among others. Drawing inspiration from these, we have taken lauryl alcohol as a prebiotically possible fatty alcohol and cetyltrimethylammoniumbromide (CTAB) as a model cationic amphiphile and studied their co-assembly using dynamic light scattering (DLS), Nile Red dye encapsulation fluorescence studies and found CTAB and lauryl alcohol to form droplet-sized aggregates capable of encapsulating prebiotically relevant molecule isoprene and other model monomers like styrene. Then we have tried to model prebiotic condition of constant electric discharge using a cathode to mimic an electron source and investigated polymerization reactions of the aforementioned model monomers using prebiotically available sulfate as a radical initiator in electrolytic conditions. We investigated the reactions using High Resolution Mass Spectrometry (HRMS) and 1H NMR and found formation of polyisoprenes which are precursors to biomolecules like terpenoids and as well as polystyrene. Role of sulfate was found to be crucial as well as no polymerization proceeded without the presence of sulfate ions. A possible mechanism for the electro-droplet mediated polymerization using a radical mechanism is proposed.

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