Nanocomposites and nanomaterials 

Structure of the Composites Based on Bacterial Cellulose and Multi Walled Carbon Nanotubes 
Polishchuk E.V.1, Shevchenko V.B.1, Nizhelska O.I.2, Voychuk S.I.3 
1 Faculty of Physics, Taras Shevchenko National University of Kyiv, Prospect Glushkova, 2, Kyiv- 03022, Ukraine 
E-mail: shevchenko@univ.kiev.ua
2 Laboratory 36 Composite Materials for Nuclear-Hydrogen Energy, Institute of Applied Physics of NASU (Sumy), room 606, building 3, Prospect Nauki, 46, Kyiv - 03028, Ukraine.
3 Department of Physiology of Industrial Microorganisms, D. K. Zabolotny Institute of Microbiology and Virology of NASU, Zabolotny Str., 154, Kyiv - 03143, Ukraine.

     Bacterial cellulose (BC), consisting of a 3-D network of oriented cellulose 2-8 nm diameter fibrils, which combine into nanofibers, can be a promising substance to produce electrically conductive composite materials with biodegradable properties. Biocompatible composite films containing carbon nanotubes (CNTs) due to their electrical conductivity can serve as sensors for communication between living tissues in the body and biomedical instruments or neuroelectronic prostheses.
The aim of our work was to create a composite material based on BC, synthesized by bacteria of the genus Gluconacetobacter sp., and multi walled CNTs, and studying the effect of the method of its preparation on the composite structure. 
The samples of composite materials were formed with wet gel films and dried films of BC and CNTs with different degrees of dispersion. Optical microscopy and scanning electron microscopy shown that the BC network acts as a matrix, containing dispersed CNTs and aggregated CNTs. Composites formed with wet BC gel and dispersed CNTs contained a continuous branched network of carbon components showing an ability for current conduction that contrasted with composites synthesized by other methods. 
X-ray diffraction analysis showed that the structure of pure BC and cellulose, which was a matrix of BC composite with CNTs have some differences. Namely, for the composite made with wet cellulose gel and dispersed CNTs, a decrease in the size of the crystallites in the cellulose and a decrease of the degree of its crystallinity were observed.