Doctoral Defense in Chemistry - Sreejith Sudhakaran Jayabhavan

Doctoral candidate:
Sreejith Sudhakaran Jayabhavan

Title of thesis:
Building Smart Materials by Tuning the Self-assembly Modes in Supramolecular Gels

Opponents:
Dr. Gareth O. Lloyd, Associate Professor at the School of Natural Sciences, University of Lincoln, England
Dr. Stefán Jónsson, Head of ARD Physicochemical Methods at Alvotech, Iceland

Advisor:
Dr. Krishna Kumar Damodaran, Professor at the Faculty of Physical Sciences, University of Iceland

Other members of the doctoral committee:
Dr. Már Másson, Professor at the Faculty of Pharmaceutical Sciences, University of Iceland
Dr. Guðmundur Gunnar Haraldsson, Professor emeritus at the Faculty of Physical Sciences, University of Iceland

Chair of Ceremony:
Dr. Birgir Hrafnkelsson, Professor and Head of the Faculty of Physical Sciences, University of Iceland

Abstract:
The astounding capacity of nature to self-assemble is a fundamental principle that is seen at many different scales, ranging from micro to macromolecular structures. The study of self-assembly continues to be a vibrant area of research, but understanding self-assembly in nature is a challenging task because of its dynamic nature. Therefore, studying the role of such interactions provides valuable insights into designing smart materials. This doctoral work aimed to study the role of various non-bonding interactions and the spatial arrangement of the functional groups in dictating the self-assembly modes in individual and multi-component low molecular weight gels (LMWGs). The primary focus was on LMWGs with functionalities such as amide, urea, thiourea, and carbamate moieties with extended hydrogen bonding capability, which could result in gel fibrils with intriguing properties. Furthermore, antibacterial agents and drug-mimicking moieties were incorporated in addition to the above functionalities, and the applications of LMWGs in sensing, antibacterial studies, and gel phase crystallization were investigated. LMWGs were designed and synthesized, and the structure-property correlation was studied using rheology, scanning electron microscopy, circular dichroism, FT-IR, UV-visible spectroscopy, and X-ray diffraction techniques. The gelation properties in the presence of metal salts were investigated, which showed that the presence of metal salts leads to the making/breaking of gels. The interactions of polymorphic drugs in gels with drug-mimicking and non-mimicking functionalities were examined to evaluate the specific role of functionalities in the crystal growth of active pharmaceutical ingredients (APIs). The self-assembly in the multi-component gels based on chiral or enantiomeric compounds was studied in detail and the specific co-assembly modes in mixed enantiomeric gels was confirmed by various analytical techniques. In general, the doctoral thesis aimed at understanding the crucial role of particular functionalities or substituents in tuning the gelation properties in individual and enantiomeric multi-component systems. This doctoral thesis gives a detailed outlook towards tuning the self-assembly in both individual and multi-component gels via various internal and external factors, which will help us to predict the mechanism of supramolecular gel formation and design LMWGs with tunable properties.

About the doctoral candidate:
Sreejith was born in 1996 to a family in south India. His mother, by profession, is a high school teacher of chemistry, which has always inspired him to explore the beauty of chemistry. In 2019, he pursued his master’s in chemistry from the Central University of Tamil Nadu, India. He had joined Prof. Krishna K. Damodaran’s lab in November 2019. His doctoral studies focus on analyzing the self-assembly in supramolecular gels to build smart materials.