Cellulose nanocrystals (CNCs), nanorods produced by acid hydrolysis of cellulosic sources, are emerging as a new class of functional biomaterial. CNCs present a broad range of uses, for example in composites, cosmetics, security paper and medical devices. The fascinating ability of CNCs to self-organize into a cholesteric liquid crystal phase, with a helical arrangement of the nanorods, is attracting substantial interest across different research fields. It is important from an applied point of view since this arrangement gives a photonic band gap to the final dried CNC films, but also from a fundamental soft matter physics perspective, as many details of the CNC liquid crystal formation are far from being understood.<br/>A critical problem from an analytical, and likely also from an applied perspective, is the high length polydispersity of as-produced CNC samples. In this study, we introduce a method for fractionating the CNC nanorods, utilizing the spontaneous phase separation between isotropic and liquid crystalline phases, allowing us to narrow down the length distribution. This procedure allows us to induce cholesteric order at much lower CNC concentration in the long-rod fraction without the common competition between fully liquid crystallinity and gelation. We believe that this extension of phase diagram will permit us to better control the color of the finally dispersed films, compared to the natural polydisperse samples that are now used in the community.

Fractionation of cellulose nanocrystals enhances liquid crystal ordering without promoting gelation

256th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.