Synthesis And Chiral Optical Properties Of Chiral Nematic Liquid Crystalline Phase Of Copper Nanoparticles

The noble metal nanostructures have been widely used in biosensors,asymmetric catalysis and optical devices.Therefore,the study of self assembly and optical properties has attracted much attention.The chiral nematic liquid crystals formed by the noble metal nanoparticles have great potential for their unique microstructure and physical properties.This thesis is formed by chiral two novel copper nanostructures of nematic liquid crystal phase as the foundation,through the introduction of different concentrations of cysteine chiral molecules to modify the surface,eventually forming a new chiral nematic liquid crystal phase.In this paper,we will focus on the self assembly synthesis of chiral nematic liquid crystalline phase and the influence of amino acids on their chiral structure and optical activity.The main work in this paper:In the first chapter of the thesis,we will review the background of the field,including the basis of chiral optical activity,the development of liquid crystal materials,the research progress,the basic characteristics and related applications.In this paper,we present a detailed description of the overall development of the metal nanostructures and their optical properties.In the second chapter,the chiral nematic liquid crystalline phase and the influence of amino acid molecules on the surface of hydrophilic copper nanowires were studied.At the same time,this kind of hydrophilic copper nanoparticles in a variety of solvents can be formed the hydrophilic copper nanowires nematic liquid crystal structure and the effects of different amino acids on the structure were introduced in detail.The other amino acids with different concentration can not affect the hydorphilic copper CNLC phase.the cysteine molecules can adsorb on the surface of hydrophilic plasmonic copper nanorods to transfer their chirality to the copper nanorods by S-Cu bonds,resulting in the appearance of new circulr dichroism(CD)signals in the ultraviolet(UV)region.the hydorphilic Cu-cysteine nanorods are stillable to form CNLC phase with the similar chirality with hydrophilic copper CNLC phases.When the concentration of cysteine reaches 2.5 mM,the chiral signal is the strongest.We use the hydrophobic copper nanowires were controlled by comparison confirmed that the chiral composite hydrophilic copper nanowires due to its surface characteristics and unique geometry and optical properties of chiral showed very strong.In the third chapter,Copper nanoparticles can also spontaneously form chiral nematic liquid crystalline phases,Under the action of cysteine,the CD signal is moved and strengthened,and the change of the optical activity is due to the adsorption of cysteine.However,the change of interaction does not destroy the chiral nematic liquid crystalline phase.This proves that the control of the optical activity can be achieved by controlling the concentration of cysteine.