Figure 3: (a) The dependence of average diameter of composite nanoparticles (15% NIPAAm) on temperature. The error bars show standard deviations of particles made in three different batches. The transition temperature is around 32°C. There size transition is nearly reversible. (b) Drug release versus time curve indicating release at room temperature (yellow triangles) and at 40°C (green circles). There is no release at 25°C which is below the transition temperature of the composite particle. The cumulative fractional release is shown as an inset where the maximum amount of drug release value is taken at 40°C for 10 hours; diffusion model parameters have been calculated from these data.