Mechanical Properties of Bacterial Cellulose Microfibril Bundles in Tensile Loading

Abstract

<abstract> <bold>Abstract.</bold> Mechanical properties of the cellulose microfibril are yet to be characterized under tensile loading because of its submicron size. Two major challenges are (a) isolating a cellulose microfibril, or bundle of cellulose microfibrils, and fastening them onto a test device for subsequent mechanical testing, and (b) developing a miniature tensile testing device having submicron displacement and submicronewton force resolutions compatible with biological nanofiber samples. Since Gluconacetobacter xylinum (ATCC 53582) deposits cellulose in a media, the cellulose network can be incorporated with a test setup bypassing the challenging sample preparation procedures (Zamil et al., 2013). By maintaining a lamellar flow and by static culturing of inoculated Hestrin & Schramm (HS) medium over a test device, a network of cellulose microfibrils were grown directly on the test device’s sample area. Static culture method was found to be more effect considering the number of cellulose microfibrils and their adherence to the device. Few preferred oriented cellulose microfibril bundles were kept by cutting the rest using focused ion beam (FIB) milling. Mechanical testing was performed using a piezoelectric actuation-based microelectromechanical system (MEMS) tensile testing device that was designed and fabricated for submicron scale biological samples (Zamil et al., 2013). Here preliminary results under tensile loading are presented.