New liquid-free proton conductive nanocomposite based on imidazole-functionalized cellulose nanofibers

The first successful attempt to synthesize a new proton conducting polymeric nanocomposite film based on pure cellulose nanofibers (CNF) as a polymer matrix functionalized on their surface with imidazole molecules (Im) as a dopant, was made. The 2CNF-Im nanomaterial contains on average one molecule of imidazole per 2 glucose units from cellulose chains. Water evaporation and thermal stability of 2CNF-Im were studied by thermogravimetric analysis (TGA and DTG) and differential scanning calorimetry (DSC). The temperature dependence of electrical conductivity was studied by the impedance spectroscopy. At 140 degrees C, the 2CNF-Im nanocomposite has a maximum conductivity of 7.0 x 10(-3) S/m, i.e. four orders of magnitude higher than that of non-functionalized CNF matrix. The newly synthesized cellulose nanocomposite exhibits high electrical and thermal stability. In 2CNF-Im, the activation energy of the proton transport process is the lowest compared to the previously synthesized imidazole-functionalized composites based on other pure cellulose materials and equals 0.62 eV. The synthesized nanomaterial is liquid-free solid polymer electrolyte showing proton conductivity above the boiling point of water.

Automated summary

The study successfully synthesized a new proton-conducting polymeric nanocomposite film with high electrical and thermal stability. The newly synthesized material showed the highest conductivity at 140 degrees Celsius, being four orders of magnitude higher than that of the non-functionalized matrix.