Free-standing poly (N-isopropylacrylamide) microgel-based etalons

Poly (N-isopropylacrylamide-co-acrylic acid) (pNIPAm-co-AAc) microgel-based free-standing etalons have been developed by fabricating etalons on a solid support that has been coated with a sacrificial polymer layer. Therefore, the etalon could be easily removed from the solid substrate upon dissolution of the sacrificial layer. We show that the free-standing etalons retain the optical properties, and the temperature/pH responsivity, of the etalon before its removal from the solid substrate. Furthermore, we show that the free-standing etalons could be transferred to a variety of different substrates, with different chemistries and shapes. We go on to show that the free-standing etalons could be loaded with a small molecule model drug Crystal Violet (CV), transferred to a hydrogel, and triggered to release the CV in a pH-dependent fashion. In the future, these novel free-standing films can be used for sensing, as transferable optical materials, and will be further developed into drug delivery platforms.