Preparation and Regulation of Temperature-Sensitive Organogel for Temperature-Controlled Information Displays and Smart Temperature Labels.

Temperature-sensitive gels are attractive in various fields, including smart windows, information encryption, and actuators. Herein, we select ethylene glycol as the solvent and prepare a poly(4-acryloylmorpholine) (PACMO) organogel with UCST phase transition behavior via photopolymerization. This temperature-sensitive organogel, with transition temperatures adjustable between 10 and 62 °C, displays high temperature sensitivity, a narrow transition window, and excellent cycling stability. The incorporation of comonomers, cosolvents, and cross-linkers significantly affects the transition behavior of the organogel through changing the transition temperature or broadening the transition window from 2 to 25 °C. Variable-temperature infrared spectroscopy and theory calculations reveal that the ether bond of PACMO competes with the intermolecular hydrogen bonds of ethylene glycol. As the temperature rises, the intermolecular hydrogen-bond interaction between ethylene glycol molecules weakens, while the hydrogen-bond interaction between the ether bond and ethylene glycol strengthens, leading to changes in transparency of the organogel. The applications of the organogel in the fields of temperature-controlled information displays and smart temperature labels are demonstrated. This design broadens the types of temperature-sensitive gel materials to organogels, opening a pathway toward applications with multifunctional optical requirements.