Course-PM

MCC080/FIM850 Liquid crystals, physics and applications lp4 VT24 (7.5 hp)

Course is offered by the department of Microtechnology and Nanoscience

Contact details

Per Rudquist, Examiner and lecturer
per.rudquist@chalmers.se

Phone: +46 31 772 3389
Room F6109

Student representatives:

 

 

Course Purpose:
We aim to give an introduction to the physics, and the most common applications, of liquid crystals. In addition to the basic course contents, we also give an overview of the state-of-the art of the field, both within research and industry. Parts of the course material and content is therefore continuously updated. Through a large number of examples and demonstrations during lectures and laboratory exercises, we aim to stimulate the student to see the connections to other courses and fields of science. The course gives a good basis for future advanced studies of liquid crystals but we hope that you will find the skills and knowledge gained in this course most rewarding, also for future activities within other disciplines.

 

Learning outcomes:

After completion of this course, the student should be able to

• describe the structures, symmetries,  order, and phase transitions  of the most important liquid crystal phases

• understand the basic electric, elastic, and optical properties of liquid crystal materials

• explain the structure and function of liquid crystal displays and devices.

• experimentally identify the most important liquid crystal phases

• carry out basic optics and electrooptical measurements of liquid crystals

• explain the main fabrication steps in liquid crystal display manufacturing

• discuss questions and problems related to liquid crystal science and applications, and to propose solutions/draw sound conclusions by combining knowledge of liquid crystal physics, optics, symmetry arguments, thermodynamics, electromagnetism, condensed matter physics, and other relevant fields of science

 

Content:

Most people are familiar with the fact that matter can exist in three different states: solid, liquid and gas. However, this is a simplification, and under extreme conditions other forms of matter can exist, e.g. plasma at very high temperatures or superfluid helium at very low temperatures. But we do not have to go to these extreme conditions to find new forms of order in matter. In liquid crystals, which are anisotropic fluids, the molecular order lies between those of the isotropic liquid and the crystal and the classification of liquid crystals is based on their degrees of orientational and positional order. From a basic physics point of view these materials are of large interest and have contributed to the modern understanding of phase transitions and critical phenomena, and to the knowledge about order phenomena in one, two, and three dimensions.

To common people liquid crystals are today almost synonomous to flat panel displays (Liquid Crystal Displays, LCDs) for TVs, computers, mobile phones, and other electronic equipment. But there is also a rapid development of other types of application, for instance in telecommunication, and photonics. Liquid crystalline structures are readily used as templates for synthesis of advanced porous materials and recently liquid crystal have also been proposed as matrices for positioning and aligning nanoparticles of different shapes, i.e. for new types of composite materials and metamaterials. 

Liquid crystals consitute a unique form of soft matter. The existence of life is directly dependent on self-organizing soft matter and here liquid crystalline systems play vital roles. One example is cell membranes which consist of so-called lyotropic liquid crystals. Another is DNA that under certain conditions form liquid crystals. Maybe the origin of the extremely long DNA molecule can be found in self organisation and liquid crystal formation of small molecules.

The course will give a basic understanding of the physics and different applications of liquid crystals. The content ranges from the history of liquid crystal science, from the first observations in the late nineteenth century, via the development of theories of the liquid crystalline state, the development of liquid crystal displays and examples of today´s state of the art research. After decades of strong focus on liquid crystals for displays, a large part of the liquid crystal research is today shifting towards nanoscience, colloidal systems, biological systems, and, on the applicational side, towards photonics and microwave electronics.


The course will stress on how knowledge in optics, thermodynamics, electromagnetism, vector analysis, symmetry analysis, etc. constitutes the basis for the very rapid development of liquid crystal displays and devices that we use every day. Furthermore, the course will through laboratory exercises and demonstrations give an introduction to the manufacturing of LCDs.


1. Physical properties of liquid crystals and basic theory

Phases and phase transitions; anisotropic materials; symmetry aspects; optics; elasticity, electrooptics of liquid crystals; ferro-, and antiferroelectric liquid crystals; the research front.

2. Liquid crystal applications

LCDs, present and future displays, 3D-displays, demonstrations, manufacturing of devices, non-display applications, thermochromics, Kevlar, chirality detection

3. Lab project

Problem based laboratory work, Prestudy, planning, ~8h work in the laboratory, plus written report, oral presentation

 

Course Design

The course material will be presented and discussed during lectures focussing on  different topics and aspects of liquid crystal physics and applications. Lectures are scheduled for Mondays 13:15-15:00 and Thursdays 08:00-11:45 and will be held in FL71, FL72, and FL64 in the Physics building. Please check location of each lecture under Course Summary below. Some of the lectures will be "problem based", i.e. the course students will  through discussions and questions together find answers to specific presented problems. Lecture notes will be available on Canvas. I recommend the students to go through the lecture notes before each lecture.

LABORATORY DEMONSTRATIONS: Polarised light microscopy, liquid crystal textures, phase transitions (1) and electrooptic switching of liquid crystals (display physics) (2)will be further treated during two laboratory demonstrations á 2h. These will be held in the LC Lab F6207 in Forskarhuset Fysik. Depending on the number of students in the course a few extra lab-demonstration slots might be needed. If so, these extra slots will be scheduled to minimise possible collisions with other courses. The laboratory demonstrations are compulsory and active participation is required for pass. No material to be submitted in relation to these demonstrations,.

HOMEWORK ASSIGNMENTS: There will be 3 sets of homework assignments for further training. These homework assignments also constitute part of the final grade. Some questions are quite straight forward, while other questions requires combinations of knowledge/material from several different lectures in the course, relating to the stated learning outcomes. Another purpose of the homework assignments is to help/stimulate the course students to spread the study load in the course over time. Note that the points (up to 7.5 points) for homework assignments are NOT bonus points on the exam. The homework assignments are part of the examination, see below. Deadlines are sharp as I will go through the answers in class on the first occasion after the deadline for each set of homework problems. 

 

LABORATORY PROJECT: The course students will also carry out a compulsory laboratory project in groups of ~2 students on a specific topic, where knowledge from the course will be applied to solve a certain LC problem, or study a certain LC phenomenon,  in the laboratory. The Lab Projects are carried out in the LC Lab F6207 in Forskarhuset Fysik. This relates to the hands-on training part of the course. A written report of maximum 5 pages should be submitted after the laboratory  project. The projects will also be presented during a course seminar (15 minutes/project) in the last week of the study period. The laboratory project is also part of the final grade, see below. 

 

 

Literature

• Copies of lecture notes, OH slides in pdf-format.

•.   Collings&Hird: Introduction to Liquid Crystals, Taylor&Francis 1997 (Recommended, but not followed to 100%);

•.   S.T.Lagerwall, P.G.Rudquist, D.S.Hermann: "Liquid crystals", in Encyclopedia of optical Engineering, Marcel Dekker Inc. 2003)

 

Suggested reading,   parts of:

J. Prost, P.G. de Gennes: The physics of liquid crystals, Oxford 1993;

S.Chandrasekhar: Liquid Crystals, Cambridge 1976, second edition 1992;

E.B. Priestley, P. Wojtowicz, P.Sheng: Introduction to Liquid Crystals, Plenum, NY 1975;

D.Demus et al. (editors) Handbook of Liquid Crystals, Volume 1-3, Wiley VCH, 1998;

S.T.Lagerwall: Ferroelectric and Antiferroelectric Liquid Crystals, Wiley VCH 1999.

 

Examination form

Written exam                         70% of grade

Home work assignments      15% of grade
Lab project                             15%. of grade

Laboratory exercises.            Pass

 

Grading:

The maximum score on the written exam is 35 points

The individual homework assignments may give a maximum of 7.5 points

The lab-project* (in groups of 2 students) may give a maximum of 7.5 points. Students are individually assessed and the students in a project group may get different scores.

The total number of points from the written exam, the homework assignments, and the lab projects constitutes the basis for the final grade:

0-19.5      NOT PASS,
20-29.5    Grade 3,
30-39.5    Grade 4,
40-50       Grade 5

Prerequisites

Basic knowledge on Optics, Electromagnetics, Thermodynamics, Solid state physics

 

 

Schedule

TimeEdit

 

Link to syllabus in Studieportalen