Scientists from the Raman Research Institute (RRI), an autonomous institute of the Department of Science and Technology, have published a study in the Journal of Colloid and Interface Science demonstrating how temperature shocks can erase memory imprints in jammed systems. The research team, including Sonali Kawale (first author and PhD student) and Ranjini Bandyopadhyay (co-author), used microgel particles that can absorb 300-500 times their weight in water, similar to materials used in diapers and sanitary napkins.
The study found that applying rapid temperature ramp rates (thermal shocks) causes particles to rearrange, sending jammed systems into temporary liquid states that erase memory of different paths navigated during heating and cooling processes. The researchers observed asymmetry in the path suspension followed to reach the target temperature of 20°C during heating versus cooling, with no mirror symmetry between the processes.
The practical application focuses on drug delivery systems where microgel particles are loaded with drugs when cool and swollen, then collapse when rising above 34°C (slightly below body temperature), squeezing out medicine at targeted sites like tumors. This targeted drug release reduces side effects, and understanding how thermal shocks influence structural recovery could enhance these systems. The microgel particles were synthesized in a three-neck round-bottom flask, ground to fine powder, suspended in water, stirred for 24 hours, sonicated for 15 minutes, and refrigerated at 4°C where they remain stable for months.
Future work will study how path-dependent dynamics of jammed systems depend on mechanical shocks compared to thermal shocks. The publication reference is 10.1016/j.jcis.2026.139830.