Introduction
Liquid crystals when heated have structure of solids but by freedom of movements as in liquids at sharp transition temperatures. The dissimilar alignments of liquid crystal molecules are responsible for the diverse orders. Such solution properties are used in our modern electronic devices as calculators, cellular phones, laptops, mobile media players
Main content
Solids usually pass openly from solid to liquid phase on heating. Instead of this several substances as polymers when heated pass through an intermediate liquid crystalline phase that has structure of solids but by freedom of movements as in liquids. The partial orderliness in it makes it extremely viscous and has properties of both liquid and solid phases. Region in which they exhibit above property is marked via sharp transition temperature. We will be considering molecular principles of liquid crystals through special optical properties.
F. Reintzer a botanist the year (1888) was the 1st to examine this while handling organic compound: cholesteryl benzoate, which on heating melted at 1450C to a viscous milky liquid. But on reaching 1790C the liquid became clear. On cooling it repealed. For example it turns viscous and milky at 1790C, while the liquid solidifies at 1450C. Today this phenomenon is termed 'liquid crystal'. Most of our modern electronic devices are depends on these technologies: liquid crystal displays (LCDs) and light-emitting diodes (LEDs).
The principles liquid crystal operates
For polymers, they pass through intermediate liquid crystalline phase that has both structures of solids in addition to freedom of motion as liquids; it can be accounted for via their partial ordering, therefore the sharp conversion temperature they have. The weak intermolecular forces, which hold the molecule mutually in liquid crystal, are simply affected via temperature, pressure and electrical field changes. There are different kinds of the liquid crystalline phases, depending on the orientation and alignments. Polymers have long, elongated, rodlike molecules, through polar groups atimes [for example C=O, C=N, COOH, R-O-R, OH, CONH, C-X]; therefore by intermolecular forces [H-bondings, van der Waals forces and dipole-dipole attractions]. In ordinary situation polymers are oriented randomly. [NB: Lengths of the molecules are greater than their widths]. But the liquid crystalline phases have dissimilar orderings. The different alignments of liquid crystal molecules are responsible for the different orders. They can be demonstrated therefore:
Fig: The principles liquid crystal operates
Nematics have its molecules in one dimensional ordering, aligned along their long axes as handful of pencils by non-aligned ends. Smetic molecules have 2 dimensional orderings; molecules are aligned along their long axes and in layers. Molecules of cholesteric are in successive layers. Their orientation is at trait angles to adjacent layers, therefore no repulsive interactions and provides a screwlike axis.
Some importance and applications of solution properties of polymers
The liquid crystal displays (LCDs) in several of our modern electronic devices as calculators, cellular phones, laptops, mobile media players employ the solution property. They have wide applications in temperature and pressure sensors in addition to displays of electrical devices of the above mentioned and wireless devices. They are utilized in monitoring devices for example the cholesteric liquid crystal is utilized in monitoring temperature changes in situations where conventional techniques aren't possible. Like taking skin temperature of infants; detecting hot spots in micro-electronic circuits that can signal presence of flaws.
Some molecules of liquid crystals
(i)
CH3O CH N C4H9 [Changes between solidification-viscous liquid] at 21-470C
(ii)
CH3 (CH2)7 O COOH [Changes between solidification-viscous liquid] at 108-1470C
(iii) Dow Industrial Specialty Polymers in Electronics Applications Activity A: Discover details of (iii) Dow Industrial Specialty Polymers in Electronics Applications
More examples
(i) Solutions of the polymer polyvinyl alcohol (PVA) and polyvinyl acetate can be made into gels via addition of a borax solution. Borax cross-links the polymer chains, to provide interesting properties of gels.
(ii) 'Slime' is a polyvinyl alcohol polymer.
(iii) 'Glue' is a polyvinyl acetate polymer.
Tutorsglobe: A way to secure high grade in your curriculum (Online Tutoring)
Expand your confidence, grow study skills and improve your grades.
Since 2009, Tutorsglobe has proactively helped millions of students to get better grades in school, college or university and score well in competitive tests with live, one-on-one online tutoring.
Using an advanced developed tutoring system providing little or no wait time, the students are connected on-demand with an expert at https://www.tutorsglobe.com. Students work one-on-one, in real-time with a tutor, communicating and studying using a virtual whiteboard technology. Scientific and mathematical notation, symbols, geometric figures, graphing and freehand drawing can be rendered quickly and easily in the advanced whiteboard.
Free to know our price and packages for online chemistry tutoring. Chat with us or submit request at [email protected]
tutorsglobe.com categories of fruits assignment help-homework help by online fruit tutors
www.tutorsglobe.com offers formal method model homework help, assignment help, case study, writing homework help, online tutoring assistance by computer science tutors.
efficiency ratios are employed to try to assess how effectively the several resources of the business are managed.
Flowering Plants tutorial all along with the key concepts of Features of Flowering Plants, steps in the life-cycle of flowering plants, Gymnosperms and Angiosperms.
tutorsglobe.com steps for evaluating capital budgeting assignment help-homework help by online capital budgeting and project planning tutors
www.tutorsglobe.com offers Data Objects Attributes and Relationships homework help, assignment help, case study, writing homework help, online tutoring assistance by computer science tutors.
www.tutorsglobe.com offers Level of SRS homework help, assignment help, case study, writing homework help, online tutoring assistance by computer science tutors.
tutorsglobe.com dislocation of joints assignment help-homework help by online bones and joints tutors
online mcat exam preparation course and online mcat tutoring package offered by tutorsglobe are the most comprehensive and customized collection of study resources on the web, offering best collection of mcat practice papers, quizzes, mcat test papers, and guidance.
Origin, Evolution and Structure of the Solar System tutorial all along with the key concepts of Sun's Interior, Model of the Solar Interior, Origin, Evolution and Structure of the Planets, Pre-Solar Nebula, Formation of Planets
tutorsglobe.com laboratory diagnosis of brucellosis assignment help-homework help by online brucellosis tutors
tutorsglobe.com structure of dna assignment help-homework help by online cell biology and genetics tutors
Scientific methods of investigation tutorial all along with the key concepts of Observing and Communicating, Consensus and Keeping Record of Investigation
Physical Parameters Relevant to Water Analysis Notable Physical Parameters of Water, Method of Turbidity Determination, Standard colour solutions, Applications of Colour Data
www.tutorsglobe.com offers free assignment help for vogel’s approximation method, unit cost penalty method, operation research subject.
1933691
Questions Asked
3689
Tutors
1462054
Questions Answered
Start Excelling in your courses, Ask an Expert and get answers for your homework and assignments!!