| 초록 |
The pH (acidity/alkalinity) and type of acid are crucial parameters affecting the thermodynamics, kinetics, and reaction mechanism of acid-base systems. Herein, we report the selective swelling of polystyrene-b-poly(2-vinyl pyridine) (PS-b-P2VP) photonic crystals, which produces different morphologies with a change in pH or type of acid, based on Henderson–Hasselbalch principles and Coulomb coupling between pyridiniums and the conjugate bases. The thickness and refractive index of P2VP layers changed with a change in H+ concentration or the hydration energy of the conjugate bases. Since the different morphologies produce distinct structural colors, the pH and type of acid can be directly identified visually. Furthermore, the structural color is affected by not only the molecular weight of PS-b-P2VP, but also the cross-linking of the P2VP layers, which can shift the structural color wavelength, thereby changing the sensitivity to pH. |
