Polysaccharide nanocrystals: colloidal building blocks for bottom-up engineering of complex structures

CFM Colloquium series

Microphase separation into well-defined patterns with nanometer features occurs in a wide variety of amphiphilic block copolymers, in bulk or in selective solvents, because of repulsive forces between unlike segments and conformational entropy loss. Analogous to block copolymers, polysaccharide nanocrystals with end-tethered polymers take advantage of enhanced mechanical properties and precision self-assembly of anisotropic colloids. In this regard, cellulose nanocrystals (CNCs) are a unique system for exploring self-assembly of colloidal analogues of both diblock and triblock copolymers since CNCs inherently form cholesteric liquid crystal (LC) phases in suspensions. Our research focuses on the extraction of CNCs from a variety of sources, end-group functionalization and structural examination of their LC phases. Depending on CNC and end-tethered polymer type, we observe a variety of LC phase characteristics, including changes in critical concentration for LC phase formation, domain size and pitch. We aspire to use end-tethered CNCs as building blocks for assembling chiral metamaterials with helicoidal morphologies for applications in chiral biosensing.