A new application of Krafft point concept: an ultraviolet-shielded surfactant switchable window†
Abstract
We report thermo-responsive gels of polyacrylamide (PAAm) with ionic surfactants in mixed water and ethylene glycol (W–EG) solvents as smart windows to solubilize ultraviolet absorbents for UV shielding materials. The Krafft point (TK) of the ionic surfactants determines the phase transition that switches the transparency and opacity of the gels. The TK can be flexibly tuned within a wide temperature range (6–75 °C) with high predictability by changing the surfactant or adjusting the ratio of W–EG solvents.