Dehydration of bacterial cellulose and the water content effects on its viscoelastic and electrochemical properties

Abstract

Bacterial cellulose (BC) has interesting properties including high crystallinity, tensile strength, degree of polymerisation, water holding capacity (98%) and an overall attractive 3D nanofibrillar structure. The mechanical and electrochemical properties can be tailored upon incomplete BC dehydration. Under different water contents (100, 80 and 50%), the rheology and electrochemistry of BC were evaluated, showing a progressive stiffening and increasing resistance with lower capacitance after partial dehydration. BC water loss was mathematically modelled for predicting its water content and for understanding the structural changes of post-dried BC. The dehydration of the samples was determined via water evaporation at 37 °C for different diameters and thicknesses. The gradual water evaporation observed was well-described by the model proposed (R ² up to 0.99). The mathematical model for BC water loss may allow the optimisation of these properties for an intended application and may be extendable for other conditions and purposes.

Keywords:

• Bacterial cellulose
• dehydration
• mechanical
• electrochemical

Classification:

• 20 Organic and soft materials (colloids
• liquid crystals
• gel
• polymers)
• 102 Porous / Nanoporous / Nanostructured materials
• 211 Scaffold / Tissue engineering / Drug delivery

Acknowledgements

Ana R. Rebelo was supported by the PhD studentship of graduate school of Loughborough University.

Notes

¹ Percentages calculated based on the expression $\frac{k_{D=5mm}-k_{D=8mm}}{k_{D=5mm}}\times 100\%$

² Percentages calculated based on the expression $\frac{k_{T=2mm}-k_{T=8mm}}{k_{T=8mm}}\times 100\%$