Preparation of cellulose-based fluorescent aggregations with various morphologies and their microstructure-correlated fluorescence behavior.

We provided an efficient method for preparing fluorescent materials with high specificity. Firstly, the cellulose-based aggregations with adjustable morphologies and sizes were obtained by cross-linking copolymerization and self-assembly. Then, after encapsulating the fluorescein isothiocyanate (FITC) into the hydrophobic microregions of the cellulose-based aggregations by ultrasound/dialysis method, a series of cellulose-based fluorescent aggregations with different morphologies was obtained. The flower-like, tentacle-like, microsphere, hollow sphere, coral-like and solid sphere fluorescent aggregations could be obtained by changing the mass ratio of cellulose to gelatin, the degree of alkylation and the length of the alkyl chain. Scanning electron microscope (SEM), Dynamic light scattering (DLS), UV-vis and Zeta potential confirmed the formation of the cellulose-based aggregations with different morphologies and sizes, which provided basis for the successful encapsulation of FITC. The flower-like fluorescent aggregation showed the maximum fluorescence intensity. This was due to the rigid structure of cellulose, electrostatic repulsion, hydrogen bonding, and the larger surface area in flower-like aggregation, which was conducive to inhibiting π-π stacking and hydrogen bonding interaction of FITC, thus promoting the electron radiative transition. Also, cellulose-based fluorescent aggregation could be processed into fluorescent fiber, coating and printing pattern, and had potential applications in information storage, scene warning, and special fiber.