Fig. 6
From: Onion-like multilayered polymer capsules synthesized by a bioinspired inside-out technique
Temperature-responsive release of dye from a two-layer DMAA–NIPA capsule. Here, DMAA is the inner layer and NIPA is the outer layer. At 40 °C (above the LCST of NIPA), the pores in the outer NIPA layer are closed; thus, the dye remains in the capsule. This is indicated by the schematic, and the corresponding micrograph shows a dark capsule due to the turbidity of the outer layer. After a certain time (110 min for the blue curve; 780 min for the red curve), the temperature is lowered to ambient (25 °C). The pores in the NIPA layer open up, causing the dye to release. This is shown by the schematic, and in this case the micrograph shows a transparent capsule. The y-axis is normalized to the dye released into solution after a long time (2 days)
