Recent advances in nanomaterial synthesis have led to the search and development of new synthetic methods. The use of high-intensity ultrasound in chemistry offers a versatile and simple means of polymeric nanostructure synthesis. The chemical effects of ultrasound that are relevant to material synthesis arise from a phenomenon known as acoustic cavitation (the formation, growth, and violent collapse of bubbles under the influence of a sound field) which can create extreme conditions inside the collapsing bubbles, and this serves as the origin of sonochemistry. Herein, the fundamental concepts involving ultrasound, sonochemistry, and emulsion polymerization will be provided. In particular, special emphasis on sonochemical production of polymer nanocomposites and (bio)polymer microspheres and the biorelated applications of these microspheres will be given.