Polymer nanoparticles have various uses, including water treatment and sunscreen. Using a similar principle as surfactant micelles, polymeric nanoparticles have amphiphilic properties, where each molecule has hydrophobic and hydrophilic parts. When water is available, the polymer will form a polymer cell with a diameter of several nanometres inside the hydrophobic part, while the hydrophilic part is outside. On polymer nanoparticles, crosslink occurs prior to the aggregation of particles so that their stability is maintained. Amphiphilic polyurethane (APU) nanoparticles have good prospects as a remediation agent.