| 초록 |
Materials with magnetic or optical hysteresis, showing a bistable state to the external stimuli, have been widely investigated due to their potential applications including memory devices or optical switches. Here we report pH tunable photonic gels which are self-assembled from block copolymers. The general idea of this research is based on the selective swelling of block copolymer mesogels, where the solubility of one block is responsive to the change of pH. In this system, the domain spacing of the lamellar is varied with the extent of swelling. As a model system, we used protonated polystyrene-b-poly(2-vinly pyridine) (PS-b-P2VP) block copolymers forming lamellar structures. Interestingly, a very strong optical hysteresis was observed while the reflection band of photonic gels was tuned by changing pH. We anticipate that pH tunable photonic gels with hysteresis can be applicable to novel applications such as a component of memory devices, photonic switches or drug delivery vehicles. |
