| Chiral liquid crystal(LC)molecules are arranged periodically,which makes them have special ability to regulate and control light.Cholesteric liquid crystal(CLC)and blue phase liquid crystal(BPLC)are two typical chiral LCs,which have one-dimensional(1D)and three-dimensional(3D)periodic structures,respectively.Chiral LCs have been widely applied in many scientific fields such as information display,biological simulation and optical control due to their special optical properties.However,the current material systems are obsolete and the theories are conservative,which restricts their development.In this thesis,the material structures were well-designed and fabricated in the atomic and molecular level to satisfy the requirement of specific functions,according to the corresponding relationship between structure and performance.And the relevant theory and rule of material molecular structure-performance-function were obtained,which provide a new approach to develop this kind of functional materials.Here,the relationships between the structure and performance from two chiral LC materials of CLC and BPLC were explored via the investigation of the molecular design and preparation condition of the materials,basing on which many functional materials were explored.(1)A semi-rigid mercaptan was synthesized and used to prepare a polymer framework liquid crystal(PFLC)composite.The influences of the material composition and the preparation conditions on the properties of the materials were studied systematically.A bistable PFLC film was prepared,which can be switched between transparent and opaque,and the state can be maintained without external electric field.The film has excellent mechanical properties and simple process in large area.Comparing with the traditional smart film which needs constant external electric field,the energy consumption is greatly reduced.(2)We present an ingenious synthetic route with high selectivity,yield and cost-effectiveness for fabricating a rigid chiral thiol,and then successfully demonstrated a simple and effective method via thiol-acrylate chemistry to prepare a polymer stabilized cholesteric liquid crystal(PSCLCs)film with a reflection bandwidth over 2000 nm.The influence factors in fabrication procedure were systematically investigated and the mechanism was explicitly verified by SEM and EDS.Thus,this work indicates a great potential of thiol-click chemistry in designing and preparing functional materials with tailored properties for practical applications.(3)In this work,series of tailored uniaxial rodlike mesogens disfavoring formation of BPs were introduced into a BP system comprising biaxial dimeric mesogens,the BP temperature range was unexpectedly broadened over 132.0 oC.It is demonstrated that molecular synergistic self-assembly behavior of the biaxial and the uniaxial mesogens may play a critical role in achieving the ultrastable three-dimensional nanostructure of BPs.We believe that this molecular synergistic self-assembly of multi-component systems can be an extremely attractive approach to develop other multifunctional soft nanomaterials.(4)The BPLCs usually have narrow temperature ranges and need the support of substrates.In this thesis,a free-standing H-bond self-assembly BPLC film with color and shape dual-responsive behavior had been presented,whose responsive behavior is programmable,reconfigurable and visual.Here,this film was demonstrated as erasing spontaneously multicolored battery-free tablet,humidity-responsive sensor and actuator,acid gas or liquid naked-eye detecting model and equipment-free visual anti-fake model.In the future,more potential application will be exploited basing on this kind of 3D self-assembly nanomaterials with special responsive properties. |
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