By learning from nature and using bio-components, we can engineer high-performance materials with improved functionality. Cellulose nanocrystals (CNCs) stand out due to their mechanical and optical properties but are limited by their hydrophilicity and interfacial compatibility with hydrophobic polymers. I will present recent advances in surface modification routes to achieve hydrophobic CNCs through polymer grafting and surfactant adsorption. The resulting materials are characterized by contact angle, turbidity, mass spectrometry, surface plasmon resonance spectroscopy and various microscopies. Hydrophobically-modified CNCs disperse in organic solvents which opens new avenues for composite processing including solvent ball milling and melt mixing and extends the range of potential applications for these bio-based nanoparticles. Surfactant-modified CNCs effectively stabilize oil-in-water and water-in-oil emulsions which can be controlled through surfactant type and concentration. Finally, a water based �grafting-from� polymerization method can be used to graft hydrophobic polymers or responsive polymers which switch surface charge, colloidal stability and hydrophobicity with temperature, pH or by bubbling carbon dioxide through the nanoparticle suspension.

Hydrophobic and �switchable� cellulose nanocrystals

247th National Meeting (2014)

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