Incorporation of functional molecules with selective reactivity into polymers enables structural transformations that translate into tunable macroscopic properties. Here, we present our studies on polymer functionalization based on the reversible boration of triethanolamine（TEA）. Condensation of TEA with boric acid or its esters selectively forms cage-shaped borate molecule（TEAB）so-called boratrane. Performing this transformation in polymers drastically alters conformational freedom of the polymer chains, leading to large shifts in glass transition temperature（Tg）up to over 150℃. TEAB also exhibits greater polarity than TEA due to intramolecular N–B coordination, imparting higher hydrophilicity to the polymers. Consequently, TEA-containing polymers display boration-dependent solubility changes, from homogeneous dissolution to dehydration and even precipitation. In addition, the underwater boration also strongly affects thermoresponsive behavior in water.

This review discusses strategies for controlling the mechanical properties of polymeric materials through plasticization, anti-plasticization, and photo-induced modifications. Conventional plasticization reduced stiffness by enhancing molecular mobility, whereas anti-plasticization, achieved via small-molecule additives, suppresses local chain motions, resulting in improved elastic modulus while maintaining optical transparency. Detailed analyses revealed that the effectiveness of anti-plasticization depends on molecular dynamics, including additive size and interaction with polymer segments, which can modulate tensile properties such as yield stress and ductility. Additionally, photo-responsive molecules, particularly azobenzene derivatives, enabled dynamic tuning of polymer properties through photo-isomerization of azobenzene units. The photoisomerization enhanced free volume and accelerated polymer chain dynamics, leading to reductions in glass transition temperature and modulus, and even inducing solid–liquid transitions or reversible adhesion under ultraviolet light irradiation. These phenomena were supported by both experimental observations and theoretical modeling, highlighting the potential of photoactive systems for developing smart and reconfigurable polymeric materials. Overall, the studies demonstrated that controlling molecular mobility via chemical additives and external stimuli provides a versatile platform for tailoring stiffness, toughness, and phase behavior of polymers. Such approaches could be helpful for future applications in optical devices, flexible components, and responsive adhesive systems.

Biomimetics is a field of science and technology that draws inspiration from the unique functions, microstructures, and processes found in living organisms, applying these insights to cutting-edge research and development. This paper focuses on thermoresponsive biomimetic polymer materials（SLUG: Self-Lubricating Gels）designed to exhibit syneresis only below freezing temperatures, introducing their excellent anti-icing/ snow properties, long-term durability, and current applications in infrastructure facilities within heavy snowfall regions.