Vpliv fleksoelektričnosti na tekoče kristalne modre faze

Petrič, Matic (author), Ravnik, Miha (mentor)

V magistrskem delu preučujem kiralne nematske strukture tekočekristalnih modrih faz. Najprej obravnavam termodinamično stabilnost ob odsotnosti fleksoelektričnosti, ter električnosti reda in primerjam strukture dvojno zvitih cilindrov in disklinacijskih linij z obstoječo literaturo. Ob upoštevanju fleksoelektričnosti in električnosti reda v sistemu modrih faz 1 in 2 se osredotočim na induciran električni potencial, ki izhaja iz polarizacije. Potencial numerično izračunam, ga prikažem ter raziščem vplive, ki jih ima na gostoto proste energije sistema. V primeru modre faze 1 opazim vzorce potenciala, ki jih preko analize direktorskega polja identificiram ter predlagam izboljšavo za shematičen prikaz osnovne celice modre faze 1. Ob spreminjanju koeficienta fleksoelektričnosti sistema opazujem, kakšen vpliv ima to na obliko električnega potenciala ter kako se na višje vrednosti fleksoelektričnosti prilagodi ravnovesna velikost osnovne celice. Obravnava vplivov fleksoelektričnosti na modre faze razkrije obstoj pasov električnega potenciala oziroma nanokanalov, ki bi se lahko uporabljali za transport ionov.

• Language: Slovenian
• Keywords: nematski tekoči kristali, modre faze, fleksoelektričnost, električnost reda, fleksoelektrični potencial, vizualizacija
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FMF - Faculty of Mathematics and Physics
• Year: 2023
• PID: 20.500.12556/RUL-144375
• COBISS.SI-ID: 141675267
• Publication date in RUL: 17.02.2023

PETRIČ, Matic, 2023, Vpliv fleksoelektričnosti na tekoče kristalne modre faze [online]. Master’s thesis. [Accessed 26 April 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=144375

Secondary language

• Language: English
• Title: The effect of flexoelectricity on liquid crystalline blue phases

Abstract

Chiral nematic structures of liquid crystalline blue phases are observed in this master thesis. After observing the thermodynamic stability of the system with the absence of flexoelectricity and order electricity I compare the acquired double twist cylinder structures and the defect lattice with the one found in literature. After taking flexoelectricity and order electricity into account, I focus on the induced electric potential that arises. The induced potential is calculated, visualized, and further inspected in terms of the influence it has on the free energy density of the system. In the case of the blue phase 1 structure I notice patterns of the electric potential, which lead me to closely investigate the director field in those regions. An improved scheme to visualize the structure of blue phase 1 is proposed. I analyze the effects of different strengths of flexoelectricity and the effect it has on the shape of the electric potential, as well as on the optimal unit cell size. The analysis of the effects flexoelectricity has on such structures exposes the existence of a regular network of electric potential, which could be suitable for transport of ions.

• Keywords: nematic liquid crystals, blue phases, flexoelectricity, order electricity, flexoelectric potential, visualization