Nanocellulose-induced helical assembled films of a coil polymer with multistimuli response for circularly polarized luminescent security materials

Helical assemblies have attracted increasing attention to generate and amplify of helical chirality and exploit advanced circularly polarized luminescent (CPL) materials. However, the helicity induction of helical assemblies with stimuli response in random-coil polymers remains challenging, limiting the high luminescence dissymmetry factor (|glum|) development of random coil polymers for CPL-based security applications. Herein, a simple and universal approach is developed for synthesizing helical assemblies (P–X–NH2/cellulose nanocrystals (CNC) nanofilms) with stimuli response via coassembly of random-coil poly(N-propargylamide)s with amino acid residues and CNCs. The induced helical chirality intensities of the helical nanofilms are sensitively regulated by adjusting the temperature, pH, solvent polarity and water content. Characterization results demonstrated that the synergistic effect of hydrogen bonding and electrostatic interactions between the polar inducers (CNCs) and the P–X–NH2 with amide structures effectively twisted the main chain of the random-coil polymer into a cis-transoidal helical conformation. Furthermore, the CPL chiroptical film stackings are constructed by attaching the P–X–NH2/CNC nanofilms on a fluorescent Poly (N-propargyl sulfonamide) (PD)/PVA film. The excited-state CPL activity in the simple CPL chiroptical film stacking is triggered with a |glum| of up to 4.05 × 10−2. This study on helicity induction at the high-level structures from random coil provides important significant insights into the natural chirality and construction of advanced chiroptical materials.