文摘
Semicrystalline polymers (SCPs) represent a group of cheap heterogeneous nuclei for crystallization. Nevertheless, cellulose, the most abundant biogenic SCP, is notorious for its poor processability. This limits its application as the orientational guiding agent in crystallization of functional compounds. Different from current polymer engineering approaches to uniaxial SCP thin films, we explored a novel approach to the uniaxial cellulose thin film via the oriented assembly of cellulose nanocrystals (CNCs) by means of a simple dip-coating technique. This thin film successfully guides the lateral crystallization of two drug compounds, which in turn reflects the uniformity of the uniaxial CNC alignment on the macroscopic scale. Furthermore, unlike traditional SCP thin films, the assembly route driven by different external forces can lead to CNC thin films with distinct orientational characters for fabrication of patterned drug thin films. The emerging colloidal assembly route to a uniaxial SCP substrate leads to unprecedented access to design heterogeneous nuclei for oriented crystallization of functional hybrids.