Regulating the pore structure and properties of polyurethane sponge by modulating the ice crystal structure of dioxane

Abstract Degradable hemostatic sponges have emerged as the future development trend of hemostatic materials, owing to their favorable biocompatibility, biodegradability, and the capacity to avert the risk of secondary bleeding during application. Vacuum freeze‐drying technology, with its precise and controllable operation, is among the commonly employed methods for sponge preparation. In this research, an in‐situ observation approach was adopted to explore the impacts of three crucial parameters, namely freezing temperature, solvent composition, and solution concentration, on the ice crystal structure during the vacuum freeze‐drying process. The correlations between each parameter and the sponge cell structure as well as performance were summarized. The research findings reveal that a lower freezing temperature leads to smaller ice crystals. As the dimethyl sulfoxide content in the solvent rises, the ice crystals progressively transform from large irregular shapes to small circular ones. A higher solute content results in a more diminutive crystal form. The insights garnered from this research offer valuable guidance for the development and utilization of biodegradable hemostatic sponges. Highlights Regulating the ice crystal structure of dioxane by controlling freezing parameters. In situ observation of ice crystal structure using a microscope. Correlation analysis between pore structure and performance of sponges.