Site: Lomonosov Institute of
Fine Chemical Technology
86 Vernadskovo Pr.
Moscow 119831, Russia

Date Visited October 28, 1993

Report Author P.E. Cladis

ATTENDEES

WTEC:

P.E. Cladis
C. Curtin
R.R. Rice
M. Slusarczuk

HOSTS:

Professor V.A. Molochko
Dr. S.M. Pestov
Dr. Z.A. (Chernaya) Kudryashova

Telephone: (095) 437-3578
Fax: (095) 162-3241
E-mail: Flid@MITHT.MSK.SU

BACKGROUND

The Lomonosov Institute of Fine Chemical Technology was founded in 1922. There are now approximately 1,500 scientific workers and teachers, and 3,500 students in many different specialties, including the technology of organic synthesis and rare elements as well as materials for electronics. Since 1974, Professor Vadim Molochko and his colleagues have been studying the thermodynamics and phase equilibria of systems involving liquid crystals.

Professor Molochko believes that the future development of display technologies is impossible without understanding liquid crystal phase diagrams. More than 100 complete phase diagrams for binary and multicomponent systems using liquid crystals have been generated by members of his group. Molochko also contributed to the creation of some liquid crystal materials produced by Niopik.

RESEARCH AND DEVELOPMENT ACTIVITIES

The method of enlarging the temperature range of stability of the nematic liquid crystal state used, for example, in displays, is to mix several different compounds to suppress the temperature of crystallization and optimize the transition temperature to the isotropic liquid state. If the various components in the mixture separate, causing the display performance to deteriorate, the goal is to predict the solubility of different materials with each other based on a knowledge of their chemical structure and their heats of transition at the solid-liquid crystal phase transition. Professor Molochko and his colleagues study in detail the many different crystal states exhibited by alloys of these molecular compounds, paying particular attention to the two-phase region characterizing first-order phase transitions. They have also formulated a model to predict eutectic coordinates of multicomponent systems from measurements of the latent heat in binary systems.

The Molochko group's investigations are moving in three main directions: (1) development of rules to select components to make liquid crystal mixtures that have low-melting eutectics and that are liquid crystalline over the required temperature range; (2) analysis of impurities in liquid crystals, and optimization of solvent selection and technical conditions for purification of liquid crystals by recrystallization; and, in the future, (3) purification of materials through crystallization in a centrifuge (40-50 gravities), and analysis of interactions between components that lead to methods to predict phase diagrams. A classification for systems showing the nematic liquid crystal state was recently formulated by Professor Molochko.

INVESTIGATION METHODS

The investigative methods used by the Molochko group are DTA (special device, with temperatures ranging from -100 degrees centigrade to +150 degrees centigrade), DSC, microscopy (device for determination of transition temperatures mesophase-mesophase, mesophase- isotropic phase in LC mixtures with volatile components, reproduc. 0.1 degrees centigrade, Pat.), visual- polythermal analysis, HPLC, viscosimetry (temp. range from -40 degrees centigrade to +120 degrees centigrade, sample volume 0.5 ml), resistometry (temp. 0,+200 degrees centigrade), powder X-ray analysis, mass-spectrometry, and computer simulation.

REFERENCES

Molochko, V.A., S.P. Naumenkov, and S.M. Pestov. 1992. Mol. Mat. 2:57.

Molochko, V., G.M. Kurdyumov, and O.P. Chernova. 1983. J. Appl. Chem. (Rus) 56(8)1719.

Molochko, V., G.M. Kurdyumov, and O.P. Chernova. 1983. J. Appl. Chem. (Rus) 56(10)2348.

------. 1981. J. Appl. Chem. (Rus) 54(8)1835.

------. 1982. J. Appl. Chem. (Rus) 55(3)517.

------. 1977. J. Appl. Chem. (Rus) 50(1)45.

------. 1978. J. Appl. Chem. (Rus) 51(1)183.

Tchornaia, Z.A., V.A. Molochko, et al. 1981. J. Therm. Anal. 21:263.


Published: December 1994; WTEC Hyper-Librarian