[Soft Matter] Highly stiff yet elastic microcapsules incorporating cellulose nanofibrils
Microcapsules with high mechanical stability and elasticity are desirable in a variety of contexts. We report a single-step method to fabricate such microcapsules by microfluidic interfacial complexation between high stiffness cellulose nanofibrils (CNF) and an oil-soluble cationic random copolymer. Single-capsule compression measurements reveal an elastic modulus of 53 MPa for the CNF-based capsule shell with complete recovery of deformation from strains as large as 19%. We demonstrate the ability to manipulate the shell modulus by the use of polyacrylic acid (PAA) as a binder material, and observe a direct relationship between the shell modulus and the PAA concentration, with moduli as large as 0.5 GPa attained. These results demonstrate that CNF incorporation provides a facile route for producing strong yet flexible microcapsule shells.
Gilad Kaufman, Shomeek Mukhopadhyay, Yekaterina Rokhlenko, Siamak Nejati, Rostislav Boltyanskiy, Youngwoo Choo, Mike Loewenberg and Chinedum O. Osuji Soft Matter, 2017, Accepted Manuscript DOI: 10.1039/C7SM00092H Received 14 Jan 2017, Accepted 23 Mar 2017 First published online 23 Mar 2017