Novel Polymers And Their Thermoreversible Gels Based On Helical Polyisocyanates

Poly(n-hexyl isocyanate) (PHIC) is a rod polymer with a dynamic helical conformation either in solution or in bulk. Due to its unique conformation, rigid structure and liquid crystalline mesophases in solvents, PHIC has been wildly used in semiconductor, optical materials and newly type resin. However, PHIC is also used in the synthesis of rod-coil copolymers, which have been deeply studied on their self-assembled behavior, microphase separation and so on.In this study, we designed and synthesized two kinds of novel rod-coil-rod triblock terpolymers with different molecular weights and different rates between the rigid segment and flexible segment. Macroinitiators were precisely prepared from trichlorocyclopentadienyltitanium(?). The designed terpolymers were synthesized by living coordination polymerization by using these macroinitiators. Then we characterized and analyzed their thermodynamic properties, liquid crystalline performance in solvents, crystallization behavior and microphase separation. In the next step, we designed the addition of chiral compound to the synthesized polymer by using thiol-ene click chemistry. The new train of thought was raised to get the induced excessive one-handed helical structure of PHIC.Thermoreversible gels are typical soft materials. Through the changing of entanglements or self-assembled supramolecular structures with temperature, the gels can exhibit reversible sol-gel transitions. These gel materials are promising in sensor and thermosensitive materials. In this paper, we successfully prepared thermoreversible gels in different solvents by using the novel polymers. Hydrogen bonding, macromolecular entanglement and the phase separation of rod-coil structure were the driving forces to form stable thermoreversible gels. The thermoreversible gels of polymer exhibited florescence in solution and aggregation-caused quenching in gels. This characteristic realized the temperature controlled and optical visible purpose of the sol-gel transition.