Recent Progress on Regulating the LCST of PNIPAM-Based Thermochromic Materials

PNIPAM-based thermoresponsive materials have garnered significant attention in the fields of biomedicine and smart materials due to their temperature-sensitive properties. The ability to regulate their lower critical solution temperature (LCST) allows for precise control over the phase behavior of the polymer, facilitating reversible phase transitions at specific temperatures. This capability is crucial for expanding applications in various contexts, such as drug release at different environmental temperatures and color-changing windows. This review comprehensively summarizes the strategies for regulating the LCST of PNIPAM and explores its potential applications. The manuscript discusses key factors influencing phase transition from two perspectives: chain regulation and molecular incorporation, including polymer chain structure, cross-linking density, solvent properties, and the role of additives. Additionally, the impact of different preparation conditions on LCST is also introduced. Recent advancements in various regulatory mechanisms are reviewed, highlighting the advantages and disadvantages of each strategy, as well as future development directions. This review provides a systematic theoretical foundation and practical guidance for the design and development of PNIPAM with tunable LCST.