Novel conducting nanocomposites: synthesis of triphenylene-covered gold nanoparticles and their insertion into a columnar matrix

Gold nanoparticles fully covered with triphenylene-based discotic liquid crystals (DLCs) were synthesized and dispersed in a columnar matrix. The thermophysical properties of these nanocomposites, studied using polarizing optical microscopy, differential scanning calorimetry and small angle X-ray diffraction studies (SAXS), confirm their insertion into the columnar matrix. The presence of the gold nanoparticles in the triphenylene-based DLCs does not disturb the nature of the mesophase other than altering the transition temperatures. We propose that the gold nanoparticles are distributed between the domain gaps of the DLCs in random disordered manner. Interestingly the DC conductivity measurements show an enhancement of the electrical conductivity by more than a million times upon doping of the discotic liquid crystals with the triphenylene-capped nanoparticles under ambient conditions.