KAJIAN PENGARUH MEDAN MAGNET PADA TRANSISI FASE SWOLLEN LIQUID CRYSTAL ELASTOMER; STUDY OF MAGNETIC FIELD EFFECT ON THE PHASE TRANSITION OF SWOLLEN LIQUID CRYSTAL ELASTOMERS

Warsono, Kamsul Abraha

2015 | Tesis | FMIPA

The effect of magnetic field on phase transition of swollen liquid crystal elastomers was studied by Monte Carlo simulation and theoretical approach. Binary mixer was used to describe the system of swollen liquid crystal elastomers with liquid crystal as solvent and liquid crystal elastomers (LCE) as solute. The influence of magnetic field on phase transition of swollen LCE is shown in the graph of the relationship between order parameter, interaction energy (consist of nematic energy, elastic energy, coupling energy and magnetic energy), specific heat, and free energy of system (consist of free energy of isotropic mixing, free energy of nematic mixing, elastic free energy, and magnetic free energy) with magnetic field and temperature. The result showed that the magnetic field influences the phase transition of swollen LCE. The increasing of the magnetic field shift the first order phase transition to the second order phase transition, shift the temperature transition from lower to the higher, and induce the isotropic phase to the paranematic phase. If the magnetic field is increased, the order parameter will decrease and the minimum value shift to the higher value than zero (induced). In general, the increasing magnetic field cause the decrease of interction energy, unless the elastic energy of system. If the magnetic field is increased, the maximum value of the specific heat shift from the higher to the lower and the temperature transition shift from lower to the higher. Likewise the free energy, the increasing of magnetic field will change the free energy of system, unless the free energy of isotropic mixing which have constant value.

Kata Kunci : Monte Carlo simulation; theoretical approach; phase transition; order parameter; interaction energy; free energy