Further molecular dynamics simulations of thin films of Stockmayer molecules between Lennardhyphen;Jones plates are discussed when the distancehbetween the plates ranges from 2.25 sgr; to 9.5 sgr;, where sgr; is the molecular diameter, and the electric fieldEranges between 0 and 1010V/m. The solvation force is calculated as a function of the plate separationhwhenE=0 andE=109V/m and as a function of the fieldEwhenh=4.0 sgr; and 7.5 sgr;. We also study the system whenh=2.25 sgr; and 4.0 sgr; with the fieldEranging from 0 to 1010V/m and find that the monolayer system (h=2.25 sgr;) seems to undergo changes of state as the temperature is lowered at zero field or if the field is changed at low temperature. While, in the absence of a field, the molecules tend to form loops and chainhyphen;like structures with the dipoles parallel to the wall, a strong external field orients the dipoles along the field so that the longhyphen;range repulsive interaction appears to induce a transition to an imperfect (twohyphen;dimensional) triangular lattice at low temperature. In between these states, at low temperatures and high fields, the molecules are packed in parallel chains with their moments perpendicular to the field and in lsquo;lsquo;ferroelectric domainsrsquo;rsquo; of opposite polarization.
展开▼
