Organization of nematic liquid crystalline phase by in-situ synthesis and assembly of gold nanocrystal

In this present article, we report the phase ordering and assembly of the nematic liquid crystalline phase of MBBA [N-(4 methoxy benzylidene)-4-butylaniline] in the presence of Gold nano-crystals (AuNCs) synthesized in situ within MBBA without incorporation of any external reducing agent or stabilizer. AuNCs formed in this growth protocol exhibit assembled structures as observed by Scanning Electron Microscopy (SEM). The most important observation that has emerged through our experiments is an ordering of the nematic liquid crystalline phase to a completely different phase in the MBBA-AuNC composite system which is in alignment with our observations from Optical Polarization Microscopy (OPM, SEM, and Differential Scanning Calorimetry (DSC) study. The emergence of smectic-like ordering in the MBBA- AuNC composite system at a relatively higher concentration of Au precursor (≥ 40 mol %) is evident from the OPM study in contrast to the thread-like structure in nematic MBBA. DSC study further indicates a pronounced increase in isotropization temperature and enthalpy in the composite system compared to the pristine sample exhibiting better thermal stability and ordering in the composite system.