Srinivasa (Srini) Raghavan is a Professor at the University of Maryland, where he heads the Complex Fluids and Nanomaterials Group ( https://complexfluids.umd.edu). His inventions include smart fluids (e.g., fluids whose viscosity can be switched a million-fold by light), hydrogels (e.g., ones that rapidly expand in seconds), capsules (e.g., those with multiple layers or compartments) and biomaterials (e.g., polymers that gel blood). A technology invented in his lab to stop bleeding has been translated into a product (Rapid-Seal Wound Gel) that is available in pharmacies across the USA. He is an elected Fellow of the National Academy of Inventors (NAI) and the Society of Rheology (SoR).