Filler size effect in an attractive fibrillated network: a structural and rheological perspective

Vincenzo Calabrese, Marcelo da Silva, Lionel Porcar, Saffron Bryant, Zakir Hossain, Janet L. Scott, Karen Edler

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

The effect of the filler size on the structural and mechanical properties of an attractive fibrillated network composed of oxidised cellulose nanofibrils (OCNF) in water was investigated. Silica nanoparticles with a diameter of ca. 5 nm (SiNp 5) and and ca. 158 nm (SiNp 158) were chosen as non-interacting fillers of the OCNF network. These filler sizes were chosen, respectively, to have a particle size which was either similar to that of the network mesh size or much larger than it. Contrast matched small angle neutron scattering (SANS) experiments revealed that the presence of the fillers (SiNp 5 and SiNp 158) did not perturb the structural properties of the OCNF network at the nanometer scale. However, the filler size difference strongly affected the mechanical properties of the hydrogel upon large amplitude oscillatory shear. The presence of the smaller filler, SiNp 5, preserved the mechanical properties of the hydrogels, while the larger filler, SiNp 158, allowed a smoother breakage of the network and low network recoverability after breakage. This study showed that the filler-to-mesh size ratio, for non-interacting fillers, is pivotal for tailoring the non-linear mechanical properties of the gel, such as yielding and flow.

Original languageEnglish
Pages (from-to)3303-3310
JournalSoft Matter
Volume16
Issue number13
Early online date2 Mar 2020
DOIs
Publication statusPublished - 7 Apr 2020

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