Modulation of low-molecular-weight cellulose self-assembly using a nonionic amphiphilic block copolymer

Artificial nanocelluloses constructed through the self-assembly of low-molecular-weight (LMW) cellulose have emerged as sustainable nanomaterials with tailorable nanomorphologies. Herein, we demonstrate the modulation of LMW cellulose self-assembly using Poloxamer 407 (P407), a poly(ethylene oxide)—poly(propylene oxide)—poly(ethylene oxide) triblock copolymer. LMW cellulose with average degrees of polymerization of approximately 7 and 10 formed nanosheets or nanoribbons in the presence of 15% and 20% (w/v) P407, while their dimensions and aggregation states varied markedly depending on the conditions. In particular, the former LMW cellulose formed nanosheets in intimate contact with one another with poorly defined boundaries at 15% (w/v) P407, while nanosheets with irregular, stepped edges were formed at 20% (w/v) P407. Fourier transform infrared spectroscopy and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analyses suggested that P407 directly interacted with LMW cellulose and affected its self-assembly. These findings reveal that amphiphilic block copolymers can serve as effective modulators of LMW cellulose self-assembly and expand strategies for controlling the nanomorphologies of artificial nanocelluloses without chemical modification of cellulose molecules.