【摘要】 基于Landau-de Gennes理论,探究了具有垂面边界锚定情况下亚微米级球形向列相液滴中分裂核结构的稳定性。结果表明:在边界条件为强锚定且单一弹性常数近似下,球形液滴内会同时存在径向结构和环结构。根据半径的不同,两种结构会分别成为稳态,即半径较大时环结构为稳态,反之径向结构为稳态。当考虑弹性各向异性时,会出现稳态的环结构和亚稳态的分裂核结构。进一步研究表明:若考虑k24弹性项对液滴内部结构的影响,当边界锚定条件由强锚定变为弱锚定(以锚定强度w=10-4J/m2为例),在单一弹性常数近似情况下,会出现径向、环和均匀3种结构,其中径向结构为稳态,且结构之间的稳定性不受k24作用的影响;在弹性各向异性情况下,径向结构会转变为分裂核结构。另外,若不考虑k24作用时,分裂核结构仍为亚稳态;若考虑k24作用,当尺寸和弹性各向异性在一定范围内时,分裂核结构可以成为稳态。在我们的模拟计算中首次发现k24作用可以使分裂核结构成为稳态。更多还原

【Abstract】 Based on Landau-de Gennes theory,the stability of split-core configuration confined in nematic liquid crystal droplets with submicron scale under homeotropic anchoring boundary condition is investigated.Results show that there are radial and ring structures under the strong anchoring boundary condition and single constant approximation.According to the difference of the radius,the two structures will become stable respectively,i.e.,the ring structure is stable when the radius is larger,and the radial structure is stable when the radius is smaller.Under the condition of elastic anisotropy,a stable ring structure and a metastable split-core structure will appear.Furthermore,the results show that if the effect of k24 on the internal structure of the droplet is considered,when the boundary anchoring condition is changed from strong anchoring to weak anchoring(take anchoring strength w=10-4 J/m2 as an example)and under the single constant approximation,it is found that there would be three structures,i.e.,radial structure,ring structure and uniform state structure,and the radial structure is stable state,in addition,the stability among structures is not affected by the effect of k24;under the condition of elastic anisotropy,the radial structure is transformed into the split-core structure.And it is still metastable when the effect of k24 is not considered;if the effect of k24 is considered,the split-core structure can be stable when the size and elastic anisotropy are within a certain range.In our simulation,it is found that the effect of k24 can make the split-core structure become stable for the first time.更多还原