表面能对磁致胆甾相-向列相转变的影响

垂直于液晶胆甾相加磁场可以引起胆甾相-向列相转变。在有界面影响的情况下,建立了物理模型。在连续体理论的基础上考虑到表面能,对有界面的磁致胆甾相-向列相转变进行分析,得到临界磁场,并画出空间周期随外磁场的变化曲线,与没有引入表面能的理论结果进行比较后发现,由于表面能对磁致胆甾相-向列相转变的影响,临界磁场要略小于没有考虑边界的情况,且结果表明盒厚在足够薄的情况下对临界磁场的影响才会明显。

Influence of the Surface Energy on the Cholesteric-nematic Phase Transition Induced by Magnetic Field

cholesteric-nematic transition can be induced by a magnetic field which is normal to the pitch of the cholesteric liquid crystals. We make a physical model with the boundary condition. Basing upon the continuum theory, we analyse the cholesteric-nematic transition considering the surface energy. We get the threshold values of magnetic field and draw the curves which are the magnetic field change with space period. The theory result of this situation has been compared to the one that isn't referred to surface energy. We have found that the threshold values of the magnetic field in this situation are less than the ones that aren't refered to boundary condition. The reason for which is the influence of surface energy on cholesteric-nematic transition induced by magnetic field. The results suggest that the influence is apparent when the cell thickness is enough small.