[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,a Shomeek Mukhopadhyay,b Yekaterina Rokhlenko,a Siamak Nejati,a Rostislav Boltyanskiy,c Youngwoo Choo,a Michael Loewenberga and Chinedum O. Osuji*a Author affiliations * Corresponding authors a Department of Chemical and Environmental Engineering, Yale University, New Haven, USA E-mail: Chinedum.Osuji@yale.edu b Department of Geology and Geophysics, Yale University, New Haven, USA c Department of Physics, Yale University, New Haven, USA