MAJOR ACTIVITIES

• Efficient and economical repair, maintenance and upkeep of different sophisticated Analytical, Biomedical, Electronics and laboratory equipments in CDRI and SAIF-CDRI for their optimum availability. Due to non-availability of imported components/Spares, equivalent indigenous substitute were used to ensure the smooth functioning of equipments. Tracing of part of circuit and data search whenever circuit diagram/service manual is not available.

• Technical specification verification for the procurement of state of the art new equipments. Help Indenter to prepare broad based technical specification and to choose right equipment to suit their application.

• Calibration of different laboratory equipments of institute as per GLP guidelines .

RESEARCH INTEREST

Study of different physical properties like Dielectric constant, Optical transmittance , Dielectric loss and phase transition of Polymer-dispersed liquid crystal(PDLC). PDLC are relatively a new class of materials that hold promise for many applications ranging from switchable windows to projection displays. These materials, which are simply a mixture of polymers and liquid crystals, are the focus of extensive research in the display industry. PDLC’s are liquid crystal droplets that are dispersed in a solid polymer matrix. The resulting material is a sort of “Swiss Cheese” polymer with liquid crystal droplets filling in the holes. Liquid crystal-Polymer composites are very important because the introduction of polymer in LC matrix not only increases the inherent mechanical strength of the material but also changes the phase behavior along with its electro-optic properties. Conversely, the ordering present in the liquid crystal materials is also influenced by presence of polymer molecules. Polymer present in the system forms a net that affects the liquid crystal molecular ordering and the dynamics of the system considerably. This slight change in molecular dynamics and ordering of liquid crystal produces a huge change in different molecular properties like relative permittivity, dielectric strength, molecular relaxation etc. Dielectric and optical properties of such a composites are completely different from those of pure polymer and pure liquid crystal. Dielectric studies provide valuable information for probing the nature of molecular orientation and intermolecular forces of these composites.

ABSTRACT

Dielectric properties of polymer-Liquid crystal composites comprised of the polymer poly(methyl methacrylate) and low molecular mass liquid crystal, Cholesteryl Palmitate are investigated in the frequency range from 1KHz to 10 MHz and in the temperature range of 27-120oC.The dielectric permittivity and dielectric loss shows substantial changes with the addition of polymer. The significant feature is that the pure liquid crystal exhibits broad absorption, showing dielectric relaxation in the range 10-100KHz whereas the composite shows relaxation peaks at 10MHz. The percentage optical transmittance of pure liquid crystal and composite have also been measured and compared to study its phase transition behavior. The smectic phase observed in the pure liquid crystal is suppressed on formation of polymer composites. The mass spectrometry measurement does not show any abduct formation between the pure liquid crystal and the composite.