Abstract
We have performed Monte Carlo simulations to investigate the temperature dependence of the ordering of the side chains of the X-shaped liquid crystal molecules which are arranged in a hexagonal array. Each hexagon contains six side chains, one from each side of the hexagon. Each liquid crystal molecule has two, dissimilar, side chains, one that contains silicon and one that contains fluorine. Like chains attract each other more strongly than unlike chains and this drives an order-disorder transition. The system is frustrated because it is not possible to find a configuration in which all the hexagons are occupied by either all silicon or all fluorine chains. There are two phase transitions. If only pairwise interactions are included it is found that there is an interesting fluctuating phase between the disordered phase and the fully ordered ground state. This did not agree with the experiments where an intermediate phase was seen that had long range order on one of the three sublattices. Agreement was found when the calculations were modified to include attractive three-body interactions between the silicon chains.
Highlights
The Monte Carlo technique is a very suitable tool for investigating novel phase transitions in classical systems because no assumptions need be made about the type of order expected and accurate predictions can be made of the order of the transition and, where appropriate, it may be used to evaluate the critical exponents [1,2]
We have performed Monte Carlo simulations to investigate the temperature dependence of the ordering of the side chains of the X-shaped liquid crystal molecules which are arranged in a hexagonal array
In order to understand this phase diagram we present the result from typical cooling and heating runs in Figs. 3(d) and 3(e)
Summary
The Monte Carlo technique is a very suitable tool for investigating novel phase transitions in classical systems because no assumptions need be made about the type of order expected and accurate predictions can be made of the order of the transition and, where appropriate, it may be used to evaluate the critical exponents [1,2]. An order-disorder transition occurs between two honeycomblike hexagonal columnar liquid crystal phases of Xshaped molecules such as A1 and A2 [Fig. 1(a)] These molecules contain a rigid rodlike core with two incompatible lateral flexible chains. Self-assembly of such compounds leads to multicolor superlattices where the two kinds of lateral chains microphase separate into neighboring columns with polygonal shaped cross sections [9,10,11] Shaped molecule has two side chains where like side chains attract significantly more than unlike chains This leads to an order-disorder transition where the fractions of the two types of chain occupy the tiles at random at high temperature but segregate below some transition temperature.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
