Undulations in a confined lamellar system with surface anchoring.
نویسندگان
چکیده
We visualize undulations in layered systems using a cholesteric stripe phase with a macroscopic supramicron periodicity. The wave vector of stripe pattern is in the cell's plane. The undulation is induced by an in-plane magnetic field normal to the stripes. The observed displacement of layers is much larger than the value predicted by the Helfrich-Hurault classic theory. We propose a model of undulations that explains the data by finite surface anchoring of layers.
منابع مشابه
Undulations of lamellar liquid crystals in cells with finite surface anchoring near and well above the threshold.
We study the undulations instability, also known as the Helfrich-Hurault or layers buckling effect, in a cholesteric liquid crystal confined between two parallel plates and caused by an electric field applied along the normal to layers. The cholesteric pitch is much smaller than the cell thickness but sufficiently large for optical study. The three-dimensional patterns of the undulating layers ...
متن کاملسمتگیری مولکول‌های بلور مایع نماتیک در وضعیت دو بعدی و اثر چنگ زدگی‌های متناهی و نامتناهی
In this paper, the director distribution is calculated for a nematic liquid crystal, in the cell with different surface anchoring conditions and external fields. The effects of finite and infinite surface anchoring on molecular orientations for one dimensional geometry are discussed. In these situations, the planar alignment is considered. Then, in a two dimensional geometry the planar and homo...
متن کاملLamellar Diblock Copolymers on Rough Substrates: Self-Consistent Field Theory Studies
We present numerical calculations of lamellar phases of diblock copolymers (BCP) confined between two surfaces, where the top surface is flat and the bottom one is corrugated. The corrugated substrate is assumed to have a single q-mode of lateral undulations with a wavenumber qs and amplitude R. We focus on the effects of substrate roughness, parametrized by the dimensionless quantity, qsR, on ...
متن کاملDirector Structures in a Chiral Nematic Slab: Threshold Field and Pitch Variations
Abstract The liquid crystal director distribution is determined for a confined chiral nematic slab. The molecular director distribution of the field-controlled chiral nematic slab is directly calculated. The director profiles for the tilt and the twist angles, under different applied fields, are calculated in the slab with weak boundary conditions. Then, the dependence of the threshold field on...
متن کاملElectrostatically induced undulations of lamellar DNA-lipid complexes
We consider DNA-cationic lipid complexes that form lamellar stacks of lipid bilayers with parallel DNA strands intercalated in between. We calculate the electrostatically induced elastic deformations of the lipid bilayers. It is found that the membranes undulate with a periodicity that is set by the DNA interaxial distance. As a consequence the lamellar repeat distance changes resulting in a sw...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Physical review. E, Statistical, nonlinear, and soft matter physics
دوره 63 3 Pt 1 شماره
صفحات -
تاریخ انتشار 2001