History of Liquid Crystals - Revision history

Nsylvain: /* History of Liquid Crystals */

2009-07-27T23:27:13Z

History of Liquid Crystals

← Older revision		Revision as of 16:27, 27 July 2009
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	Where:		Where:
	A is a molecular parameter including the polarizability anisotropy		A is a molecular parameter including the polarizability anisotropy,
	k is Boltzmann's constant		k is Boltzmann's constant,
	v is the molar volume.		v is the molar volume.

Nsylvain: /* History of Liquid Crystals */

2009-07-27T23:26:46Z

History of Liquid Crystals

← Older revision		Revision as of 16:26, 27 July 2009
Line 48:		Line 48:
	Where:		Where:
	A is a molecular parameter including the polarizability anisotropy		A is a molecular parameter including the polarizability anisotropy
			k is Boltzmann's constant
	v is the molar volume.		v is the molar volume.

Cmditradmin: /* What is a liquid crystal? */

2009-06-25T19:37:49Z

What is a liquid crystal?

← Older revision		Revision as of 12:37, 25 June 2009
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	=== What is a liquid crystal? ===		=== What is a liquid crystal? ===

	[[Image:~~Lc_phasechange~~.~~png~~\|thumb\|300px\|Crystalline materials have both orientational and positional order. Liquid crystals can have orientational order under the right conditions.]]		[[Image:LiquidCrystal-Ordering.jpg\|thumb\|300px\|Crystalline materials have both orientational and positional order. Liquid crystals can have orientational order under the right conditions.]]
	Liquid crystals are anisotropic materials. This is important for their function in LC displays.		Liquid crystals are anisotropic materials. This is important for their function in LC displays.

Cmditradmin: /* History of Liquid Crystals */

2009-06-25T15:56:26Z

History of Liquid Crystals

← Older revision		Revision as of 08:56, 25 June 2009
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	One of the first papers about liquid cyrstals appeared more than 100 years ago.		One of the first papers about liquid cyrstals appeared more than 100 years ago.

	1888 - F Reinitzer (<ref>Montash. Chem. 1888, 9, 421</ref>) observed two melting points in cholesteryl benzoate. Today these are known as cholesteric liquid crystals.		'''1888''' - F Reinitzer (<ref>Montash. Chem. 1888, 9, 421</ref>) observed two melting points in cholesteryl benzoate. Today these are known as cholesteric liquid crystals.

	1911 - C. Mauguin (<ref>Bull. Soc. Fr. Min. 1911, 34, 71</ref>) performed and described the first electro-optical experiments involving a twisted nematic phase.		'''1911''' - C. Mauguin (<ref>Bull. Soc. Fr. Min. 1911, 34, 71</ref>) performed and described the first electro-optical experiments involving a twisted nematic phase.

	1922 - M. G. Friedel (<ref>Ann. Phys. 1922, 18, 273</ref>) recognized three kinds of LC phases and introduced a new terminology.		'''1922''' - M. G. Friedel (<ref>Ann. Phys. 1922, 18, 273</ref>) recognized three kinds of LC phases and introduced a new terminology.
	*Smectic "soapy"		*Smectic "soapy"

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	Shampoo in a bottle or soap in dish may appear irridescent. This is called a lyotropic liquid crystal in which phase transition is a function of concentration. Thermotropic liquid crystals have a phase change that is dependent on temperature. Lipid bilayers are phase transitions that are lyotropic.		Shampoo in a bottle or soap in dish may appear irridescent. This is called a lyotropic liquid crystal in which phase transition is a function of concentration. Thermotropic liquid crystals have a phase change that is dependent on temperature. Lipid bilayers are phase transitions that are lyotropic.

	1927 - W. Friederickz et al. (<ref>Z. Phys. 1927, 42, 532</ref>) described the influence of electrical and magnetic fields on smectic, nematic and cholesteric LCs.		'''1927''' - W. Friederickz et al. (<ref>Z. Phys. 1927, 42, 532</ref>) described the influence of electrical and magnetic fields on smectic, nematic and cholesteric LCs.
	Marconi Wireless Telegraph Co was awarded a patent on a light valve in 1936.		Marconi Wireless Telegraph Co was awarded a patent on a light valve in 1936.

Line 50:		Line 50:
	v is the molar volume.		v is the molar volume.

	1963 - W. Richards and G. Heilmeier (RCA Corporation)(<ref>J. Chem. Phys. 1963, 39, 384</ref>) foresaw "TV on a wall".		'''1963''' - W. Richards and G. Heilmeier (RCA Corporation)(<ref>J. Chem. Phys. 1963, 39, 384</ref>) foresaw "TV on a wall".

	Then there was a rediscovery of electro-optical effects and their applications in LC display:		Then there was a rediscovery of electro-optical effects and their applications in LC display:
	~~Dichroic dye; host guest (<ref>G. H. Heilmeier et al. Appl. Phys. Lett. 1969, 13, 46</ref>).~~
	~~Phase change displays (<ref>G. H. Heilmeier et al. Proc. IEEE. 1969, 57, 34</ref>).~~
	~~Twisted nematic field effect (<ref>J. L. Fergason US patent # 3,731,986, 1973</ref>).~~

	~~1973~~ - G.W. ~~Gray~~ et al. ~~(<ref>Electron~~. Lett. ~~1973~~, 9, ~~130~~</ref>) ~~developed LCD technology based upon cyanobiphenyls~~.		'''1969''' - Dichroic dye; host guest (<ref>G. H. Heilmeier et al. Appl. Phys. Lett. 1969, 13, 46</ref>).

	~~1977~~ - S. ~~Chandrasekhar~~ et al. ~~(<ref>Pramana 1977~~, 9, ~~471~~</ref>) ~~discovered discotic liquid crystals~~.		'''1969''' - Phase change displays (<ref>G. H. Heilmeier et al. Proc. IEEE. 1969, 57, 34</ref>).

	1991 - Pierre-Gilles de Gennes, Nobel Prize Physics 1991, studied how extremely complex forms of matter behave during the transition from order to disorder. He showed how electrically or mechanically induced phase changes transform liquid crystals from a transparent to an opaque state, the phenomenon exploited in liquid-crystal.		'''1973''' - Twisted nematic field effect (<ref>J. L. Fergason US patent # 3,731,986, 1973</ref>).

			'''1973''' - G.W. Gray et al. (<ref>Electron. Lett. 1973, 9, 130</ref>) developed LCD technology based upon cyanobiphenyls.

			'''1977''' - S. Chandrasekhar et al. (<ref>Pramana 1977, 9, 471</ref>) discovered discotic liquid crystals.

			'''1991''' - Pierre-Gilles de Gennes, Nobel Prize Physics 1991, studied how extremely complex forms of matter behave during the transition from order to disorder. He showed how electrically or mechanically induced phase changes transform liquid crystals from a transparent to an opaque state, the phenomenon exploited in liquid-crystal.

	So there is a long research history in liquid crystals and much current work as well.		So there is a long research history in liquid crystals and much current work as well.

Cmditradmin: /* History of Liquid Crystals */

2009-06-25T15:54:11Z

History of Liquid Crystals

← Older revision		Revision as of 08:54, 25 June 2009
Line 26:		Line 26:
	One of the first papers about liquid cyrstals appeared more than 100 years ago.		One of the first papers about liquid cyrstals appeared more than 100 years ago.

	F Reinitzer (<ref>Montash. Chem. 1888, 9, 421</ref>) observed two melting points in cholesteryl benzoate. Today these are known as cholesteric liquid crystals.		1888 - F Reinitzer (<ref>Montash. Chem. 1888, 9, 421</ref>) observed two melting points in cholesteryl benzoate. Today these are known as cholesteric liquid crystals.

	C. Mauguin (<ref>Bull. Soc. Fr. Min. 1911, 34, 71</ref>) performed and described the first electro-optical experiments involving a twisted nematic phase.		1911 - C. Mauguin (<ref>Bull. Soc. Fr. Min. 1911, 34, 71</ref>) performed and described the first electro-optical experiments involving a twisted nematic phase.

	M. G. Friedel (<ref>Ann. Phys. 1922, 18, 273</ref>) recognized three kinds of LC phases and introduced a new terminology.		1922 - M. G. Friedel (<ref>Ann. Phys. 1922, 18, 273</ref>) recognized three kinds of LC phases and introduced a new terminology.
	*Smectic "soapy"		*Smectic "soapy"

Line 39:		Line 39:
	Shampoo in a bottle or soap in dish may appear irridescent. This is called a lyotropic liquid crystal in which phase transition is a function of concentration. Thermotropic liquid crystals have a phase change that is dependent on temperature. Lipid bilayers are phase transitions that are lyotropic.		Shampoo in a bottle or soap in dish may appear irridescent. This is called a lyotropic liquid crystal in which phase transition is a function of concentration. Thermotropic liquid crystals have a phase change that is dependent on temperature. Lipid bilayers are phase transitions that are lyotropic.

	W. Friederickz et al. (<ref>Z. Phys. 1927, 42, 532</ref>) described the influence of electrical and magnetic fields on smectic, nematic and cholesteric LCs.		1927 - W. Friederickz et al. (<ref>Z. Phys. 1927, 42, 532</ref>) described the influence of electrical and magnetic fields on smectic, nematic and cholesteric LCs.
	Marconi Wireless Telegraph Co was awarded a patent on a light valve in 1936.		Marconi Wireless Telegraph Co was awarded a patent on a light valve in 1936.

	W. Maier and S. Saupe (<ref>Z. Naturforsch. 1959, 13a, 564</ref>) published what is now known as the Maier-Saupe theory of liquid crystals which suggests the temperature at which material move from liquid crystalline to isotropic. It is summarized in the equation:		1959 - W. Maier and S. Saupe (<ref>Z. Naturforsch. 1959, 13a, 564</ref>) published what is now known as the Maier-Saupe theory of liquid crystals which suggests the temperature at which material move from liquid crystalline to isotropic. It is summarized in the equation:
	~~Tis~~ = A/4.~~55kv2~~
	Where A is a molecular parameter including the polarizability anisotropy ~~and~~ v is the molar volume.		:<math>T_{is} = A/4.55kv^2\,\!</math>
	W. Richards and G. Heilmeier (RCA Corporation)(<ref>J. Chem. Phys. 1963, 39, 384</ref>) foresaw "TV on a wall".
			Where:
			A is a molecular parameter including the polarizability anisotropy
			v is the molar volume.

			1963 - W. Richards and G. Heilmeier (RCA Corporation)(<ref>J. Chem. Phys. 1963, 39, 384</ref>) foresaw "TV on a wall".

	Then there was a rediscovery of electro-optical effects and their applications in LC display:		Then there was a rediscovery of electro-optical effects and their applications in LC display:
Line 52:		Line 57:
	Twisted nematic field effect (<ref>J. L. Fergason US patent # 3,731,986, 1973</ref>).		Twisted nematic field effect (<ref>J. L. Fergason US patent # 3,731,986, 1973</ref>).

	G.W. Gray et al. (<ref>Electron. Lett. 1973, 9, 130</ref>) developed LCD technology based upon cyanobiphenyls.		1973 - G.W. Gray et al. (<ref>Electron. Lett. 1973, 9, 130</ref>) developed LCD technology based upon cyanobiphenyls.

	S. Chandrasekhar et al. (<ref>Pramana 1977, 9, 471</ref>) discovered discotic liquid crystals.		1977 - S. Chandrasekhar et al. (<ref>Pramana 1977, 9, 471</ref>) discovered discotic liquid crystals.

	Pierre-Gilles de Gennes, Nobel Prize Physics 1991, studied how extremely complex forms of matter behave during the transition from order to disorder. He showed how electrically or mechanically induced phase changes transform liquid crystals from a transparent to an opaque state, the phenomenon exploited in liquid-crystal.		1991 - Pierre-Gilles de Gennes, Nobel Prize Physics 1991, studied how extremely complex forms of matter behave during the transition from order to disorder. He showed how electrically or mechanically induced phase changes transform liquid crystals from a transparent to an opaque state, the phenomenon exploited in liquid-crystal.

	So there is a long research history in liquid crystals and much current work as well.		So there is a long research history in liquid crystals and much current work as well.



	== References ==		== References ==

Cmditradmin: /* What is a liquid crystal? */

2009-06-25T15:50:53Z

What is a liquid crystal?

← Older revision		Revision as of 08:50, 25 June 2009
Line 10:		Line 10:
	=== What is a liquid crystal? ===		=== What is a liquid crystal? ===

	[[Image:Lc_phasechange.png\|thumb\|300px\|]]		[[Image:Lc_phasechange.png\|thumb\|300px\|Crystalline materials have both orientational and positional order. Liquid crystals can have orientational order under the right conditions.]]
	Liquid crystals are anisotropic materials. This is important for their function in LC displays.		Liquid crystals are anisotropic materials. This is important for their function in LC displays.

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	There are many classes of liquid crystals having differing degrees of order. We need to ask if a molecule is capable of being liquid cyrstalline under certain conditions. Some molecules can be crystalline, liquid crystalline (and exist in different phases of liquid crystalline) and isotropic, depending on the conditions.		There are many classes of liquid crystals having differing degrees of order. We need to ask if a molecule is capable of being liquid cyrstalline under certain conditions. Some molecules can be crystalline, liquid crystalline (and exist in different phases of liquid crystalline) and isotropic, depending on the conditions.
	<br clear='all'>		<br clear='all'>
	[[Image:MBBA.png\|thumb\|300px\|]]		[[Image:MBBA.png\|thumb\|300px\|Methoxybenzilidenebutylaniline (MBBA) has a liquid crystal phase between 21°C and 45°C]]
	As shown in the diagram to the right there are discrete phase transitions between the crystal phase, the LC phase and the liquid phase. At each phase transition there is a corresponding heat of enthalpy for the transition. Much of the research in this area is german, as a result the letter K is often used to denote the cyrstalline phase (krystal in german). Nematic refers to the liquid cyrstalline phase (abbreviated N). Liquid phase may be abbreviated as l or I (for isotropic). Under the arrrow is temperature at which there is a phase transition. These transitions are usually quite sharp.		As shown in the diagram to the right there are discrete phase transitions between the crystal phase, the LC phase and the liquid phase. At each phase transition there is a corresponding heat of enthalpy for the transition. Much of the research in this area is german, as a result the letter K is often used to denote the cyrstalline phase (krystal in german). Nematic refers to the liquid cyrstalline phase (abbreviated N). Liquid phase may be abbreviated as l or I (for isotropic). Under the arrrow is temperature at which there is a phase transition. These transitions are usually quite sharp.

Cmditradmin: /* What is a liquid crystal? */

2009-06-24T22:25:14Z

What is a liquid crystal?

← Older revision		Revision as of 15:25, 24 June 2009
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	[[Image:MBBA.png\|thumb\|300px\|]]		[[Image:MBBA.png\|thumb\|300px\|]]
	As shown in the diagram to the right there are discrete phase transitions between the crystal phase, the LC phase and the liquid phase. At each phase transition there is a corresponding heat of enthalpy for the transition. Much of the research in this area is german, as a result the letter K is often used to denote the cyrstalline phase (krystal in german). Nematic refers to the liquid cyrstalline phase (abbreviated N). Liquid phase may be abbreviated as l or I (for isotropic). Under the arrrow is temperature at which there is a phase transition. These transitions are usually quite sharp.		As shown in the diagram to the right there are discrete phase transitions between the crystal phase, the LC phase and the liquid phase. At each phase transition there is a corresponding heat of enthalpy for the transition. Much of the research in this area is german, as a result the letter K is often used to denote the cyrstalline phase (krystal in german). Nematic refers to the liquid cyrstalline phase (abbreviated N). Liquid phase may be abbreviated as l or I (for isotropic). Under the arrrow is temperature at which there is a phase transition. These transitions are usually quite sharp.

			=== History of Liquid Crystals ===

			One of the first papers about liquid cyrstals appeared more than 100 years ago.

			F Reinitzer (<ref>Montash. Chem. 1888, 9, 421</ref>) observed two melting points in cholesteryl benzoate. Today these are known as cholesteric liquid crystals.

			C. Mauguin (<ref>Bull. Soc. Fr. Min. 1911, 34, 71</ref>) performed and described the first electro-optical experiments involving a twisted nematic phase.

			M. G. Friedel (<ref>Ann. Phys. 1922, 18, 273</ref>) recognized three kinds of LC phases and introduced a new terminology.
			*Smectic "soapy"

			*Nematic "thread"

			*Cholesteric (twisted nematic)

			Shampoo in a bottle or soap in dish may appear irridescent. This is called a lyotropic liquid crystal in which phase transition is a function of concentration. Thermotropic liquid crystals have a phase change that is dependent on temperature. Lipid bilayers are phase transitions that are lyotropic.

			W. Friederickz et al. (<ref>Z. Phys. 1927, 42, 532</ref>) described the influence of electrical and magnetic fields on smectic, nematic and cholesteric LCs.
			Marconi Wireless Telegraph Co was awarded a patent on a light valve in 1936.

			W. Maier and S. Saupe (<ref>Z. Naturforsch. 1959, 13a, 564</ref>) published what is now known as the Maier-Saupe theory of liquid crystals which suggests the temperature at which material move from liquid crystalline to isotropic. It is summarized in the equation:
			Tis = A/4.55kv2
			Where A is a molecular parameter including the polarizability anisotropy and v is the molar volume.
			W. Richards and G. Heilmeier (RCA Corporation)(<ref>J. Chem. Phys. 1963, 39, 384</ref>) foresaw "TV on a wall".

			Then there was a rediscovery of electro-optical effects and their applications in LC display:
			Dichroic dye; host guest (<ref>G. H. Heilmeier et al. Appl. Phys. Lett. 1969, 13, 46</ref>).
			Phase change displays (<ref>G. H. Heilmeier et al. Proc. IEEE. 1969, 57, 34</ref>).
			Twisted nematic field effect (<ref>J. L. Fergason US patent # 3,731,986, 1973</ref>).

			G.W. Gray et al. (<ref>Electron. Lett. 1973, 9, 130</ref>) developed LCD technology based upon cyanobiphenyls.

			S. Chandrasekhar et al. (<ref>Pramana 1977, 9, 471</ref>) discovered discotic liquid crystals.

			Pierre-Gilles de Gennes, Nobel Prize Physics 1991, studied how extremely complex forms of matter behave during the transition from order to disorder. He showed how electrically or mechanically induced phase changes transform liquid crystals from a transparent to an opaque state, the phenomenon exploited in liquid-crystal.

			So there is a long research history in liquid crystals and much current work as well.



			== References ==
			<references/>

Cmditradmin at 22:20, 24 June 2009

2009-06-24T22:20:28Z

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 </tr>
 </table>
 [[category:liquid crystals]]

Cmditradmin at 15:35, 23 June 2009

2009-06-23T15:35:38Z

← Older revision		Revision as of 08:35, 23 June 2009
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	</table>		</table>

			[[category:liquid crystals]]
	<table id="toc" style="width: 100%">		<table id="toc" style="width: 100%">
	<tr>		<tr>

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2009-06-23T15:28:27Z

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<table id="toc" style="width: 100%">
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<td style="text-align: left; width: 33%">[[Double Refraction and Birefringence|Previous Topic]]</td>
<td style="text-align: center; width: 33%">[[Main_Page#Liquid Crystals and Displays|Return to Liquid Crystal Menu]]</td>
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