Editing State of matter (section)

==Non-classical states==

=== Glass ===
{{Main|Glass}}

{{multiple image
 | image1    = Silica.svg
 | alt1      = Atoms of Si and O; each atom has the same number of bonds, but the overall arrangement of the atoms is random.
 | total_width= 400
 | image2    = SiO² Quartz.svg
 | alt2      = Regular hexagonal pattern of Si and O atoms, with a Si atom at each corner and the O atoms at the centre of each side.
 | footer    = Schematic representation of a random-network glassy form (left) and ordered crystalline lattice (right) of identical chemical composition.
}}

[[Glass]] is a non-crystalline or [[amorphous solid]] material that exhibits a [[glass transition]] when heated towards the liquid state. Glasses can be made of quite different classes of materials: inorganic networks (such as window glass, made of [[silicate]] plus additives), metallic alloys, [[Ionic liquid|ionic melts]], [[aqueous solution]]s, molecular liquids, and [[polymers]].
Thermodynamically, a glass is in a [[metastable state]] with respect to its crystalline counterpart. The conversion rate, however, is practically zero.

=== Crystals with some degree of disorder ===

A [[plastic crystal]] is a molecular solid with long-range positional order but with constituent molecules retaining rotational freedom; in an [[orientational glass]] this degree of freedom is frozen in a [[order and disorder (physics)|quenched disordered]] state.

Similarly, in a [[spin glass]] magnetic disorder is frozen.

===Liquid crystal states===
{{Main|Liquid crystal}}

Liquid crystal states have properties intermediate between mobile liquids and ordered solids. Generally, they are able to flow like a liquid but exhibit long-range order. For example, the [[nematic phase]] consists of long rod-like molecules such as [[para-azoxyanisole]], which is nematic in the temperature range {{convert|118–136|C|F}}.<ref>{{cite journal|title=Phase Transitions of Liquid Crystal PAA in Confined Geometries|author=Shao, Y.|author2=Zerda, T.W.|journal=Journal of Physical Chemistry B|date=1998|volume=102|issue=18|pages=3387–3394|doi=10.1021/jp9734437}}</ref> In this state the molecules flow as in a liquid, but they all point in the same direction (within each domain) and cannot rotate freely. Like a crystalline solid, but unlike a liquid, liquid crystals react to polarized light.

Other types of liquid crystals are described in the main article on these states. Several types have technological importance, for example, in [[liquid crystal display]]s.

===Microphase separation===
{{Main|Copolymer}}

[[File:Sbs block copolymer.jpg|thumb|right|SBS block copolymer seen with [[transmission electron microscopy]] (TEM)]] [[Copolymers]] can undergo microphase separation to form a diverse array of periodic nanostructures, as shown in the example of the [[Kraton (polymer)|styrene-butadiene-styrene block copolymer]] shown at right. Microphase separation can be understood by analogy to the phase separation between [[oil]] and water. Due to chemical incompatibility between the blocks, block copolymers undergo a similar phase separation. However, because the blocks are [[covalent bond|covalently bonded]] to each other, they cannot demix macroscopically as water and oil can, and so instead the blocks form [[nanometer|nanometre-sized]] structures. Depending on the relative lengths of each block and the overall block topology of the polymer, many morphologies can be obtained, each its own phase of matter.

[[Ionic liquid]]s also display microphase separation. The anion and cation are not necessarily compatible and would demix otherwise, but electric charge attraction prevents them from separating. Their anions and cations appear to diffuse within compartmentalized layers or micelles instead of freely as in a uniform liquid.<ref>Álvarez, V.H.; Dosil, N.; Gonzalez-Cabaleiro, R.; Mattedi, S.; Martin-Pastor, M.; Iglesias, M. & Navaza, J.M.: Brønsted Ionic Liquids for Sustainable Processes: Synthesis and Physical Properties. Journal of Chemical & Engineering Data 55 (2010), Nr. 2, S. 625–632. {{doi|10.1021/je900550v 10.1021/je900550v}}</ref>