Research Projects

In this proposal, we aim to advance the understanding concerning the gelation process in hydrogels used in biomedical applications. We propose to quantify the effect of variation in processing conditions, crosslinking method, polymer concentration and several other parameters (discussed in detail in the proposal) which influence the performance of the formed hydrogel. Well-known and biologically friendly polymer system of poly(vinyl alcohol) (PVA) - poly(vinylpyrrolidone) (PVP) blends is selected as the system of study due to its industrial importance in biomedical and pharmaceutical industry. Based on its wide applicability, it is important to have a comprehensive understanding of the selected polymer system which can form gel by both physical and chemical crosslinking process. Significant variability in the final structure and properties is reported based on the processing history of the polymer. Therefore, a priori information about the viscoelasticity, stability and load bearing capacity of the polymer blend upon change in processing conditions will be extremely helpful in careful design of the products and to improve its shelf-life. We believe to enhance the understanding of the hydrogel by connecting the mechanical property of the gel to the molecular changes. In order to achieve this goal, we plan to combine Raman spectroscopy (molecular insight) with rheology (mechanical insight) to track the structural changes while phase transition along with viscoelastic modulus. This method facilitates quantitative analysis of sample morphology due to the high sensitivity of Raman band intensities to conformational changes. Raman spectroscopy emerges as the preferred method for noninvasively exploring soft matter at the molecular level, encompassing interactions, deformations, and chemical reactions. The advantages of simultaneous measurements are evident: many soft materials exhibit sensitivity to temperature and flow history, and conducting these measurements concurrently minimizes experimental variation. The proposed research shall reveal a direct correlation between the conformational changes that results in aggregation in polymer blends and leads to increase in viscoelasticity. Furthermore, the kinetic studies of formation of microcrystalline domain, chemical crosslinking, and effect of other processing conditions can be sensitively captured by Rheo-Raman setup. The developed understanding will be extremely beneficial in connecting chemical functionality and structural changes to mechanical behaviour of a wide variety of gels and utilized by the industries in better design of the materials. The generated data will also present a new set of data for theoreticians to model the polymer behaviour while connecting the molecular structure to bulk changes.