Dielectrophoresis of cellulose nanocrystals and alignment in ultrathin films by electric field-assisted shear assembly

Ultrathin films of cellulose nanocrystals (CNCs) are obtained by using a convective assembly setup coupled with a low-strength external AC electric field. The orientation and degree of alignment of the rod-like nanoparticles are controlled by the applied field strength and frequency used during film formation. Calculated dipole moments and Clausius–Mossotti factors allowed the determination of the critical frequencies, the peak dielectrophoresis as well as the principal orientation of the CNCs in the ultrathin films. As a result of the combination of shear forces and low electric field highly ultrathin films with controlled, unprecedented CNC alignment are achieved.

Cellulose nanocrystals were aligned by shear assembly under dielectric constrains.Figure optionsDownload high-quality image (138 K)Download as PowerPoint slideHighlights
► Shear assembly can be used to obtain oriented thin films of cellulose nanocrystals.
► The rod-like nanocrystals are oriented according to a field strength and frequency.
► The low electric field strength is suitable for homogeneously oriented films.