Editing Polymer (section)

{{short description|Substance composed of macromolecules with repeating structural units}} 
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[[File:Single Polymer Chains AFM.jpg|thumb|upright=0.8|Appearance of real linear polymer chains as recorded using an [[atomic force microscope]] on a surface, under liquid medium. Chain [[contour length]] for this polymer is ~204&nbsp;nm; thickness is ~0.4&nbsp;nm.<ref>{{cite journal|first1=Y.|last1=Roiter |first2=S.|last2=Minko|doi=10.1021/ja0558239|title= AFM Single Molecule Experiments at the Solid-Liquid Interface: In Situ Conformation of Adsorbed Flexible Polyelectrolyte Chains|journal=Journal of the American Chemical Society|volume=127|issue=45|pages=15688–15689|year=2005|pmid=16277495}}</ref>]]
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|title= [[International Union of Pure and Applied Chemistry|IUPAC]] definition
|quote= A polymer is a substance composed of macromolecules.<ref name=goldbook2>{{GoldBookRef |title= polymer |file= P04735}}</ref> A macromolecule is a molecule of high relative molecular mass, the structure of which essentially comprises the multiple repetition of units derived, actually or conceptually, from molecules of low relative molecular mass.<ref name=goldbook>{{GoldBookRef |title= macromolecule (polymer molecule) |file= M03667}}</ref>
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A '''polymer''' ({{IPAc-en|ˈ|p|ɒ|l|ᵻ|m|ər}}<ref>{{cite web|title=Polymer – Definition of polymer|url=https://www.thefreedictionary.com/polymer|publisher=[[TheFreeDictionary.com|The Free Dictionary]]|access-date=23 July 2013}}</ref><ref>{{cite encyclopedia|title=Define polymer|url=https://www.dictionary.com/browse/polymer|dictionary=[[Dictionary.com|Dictionary Reference]]|access-date=23 July 2013}}</ref>) is a [[chemical substance|substance]] or [[material]] that consists of very large molecules, or [[macromolecule]]s, that are constituted by many [[repeat unit|repeating subunits]] derived from one or more species of [[monomer]]s.<ref>{{cite web|url=https://www.britannica.com/science/polymer|title=Polymer on Britannica|date=25 December 2023 }}</ref> Due to their broad spectrum of properties,<ref name="PC1">{{cite book |last1= Painter |first1= Paul C. |last2= Coleman |first2= Michael M. |title= Fundamentals of polymer science: an introductory text |year= 1997 |publisher= Technomic Pub. Co. |location= Lancaster, Pa. |isbn= 978-1-56676-559-6 |page= 1}}</ref> both synthetic and natural polymers play essential and ubiquitous roles in everyday life.<ref name="MBB1">{{cite book |last1= McCrum |first1= N. G. |last2= Buckley |first2= C. P. |last3= Bucknall |first3= C. B. |title= Principles of polymer engineering |year= 1997 |publisher= Oxford University Press |location= Oxford; New York |isbn= 978-0-19-856526-0 |page= 1}}</ref> Polymers range from familiar [[synthetic plastic]]s such as [[polystyrene]] to natural [[biopolymer]]s such as [[DNA]] and [[protein]]s that are fundamental to biological structure and function. Polymers, both natural and synthetic, are created via [[polymerization]] of many small molecules, known as [[monomer]]s. Their consequently large [[molecular mass]], relative to [[small molecule]] [[compound (chemistry)|compound]]s, produces unique [[physical property|physical properties]] including [[toughness]], high [[rubber elasticity|elasticity]], [[viscoelasticity]], and a tendency to form [[Amorphous solid|amorphous]] and [[crystallization of polymers|semicrystalline]] structures rather than [[crystal]]s.
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Polymers are studied in the fields of [[polymer science]] (which includes [[polymer chemistry]] and [[polymer physics]]), [[biophysics]] and [[materials science|materials science and engineering]]. Historically, products arising from the linkage of repeating units by [[covalent]] [[chemical bond]]s have been the primary focus of polymer science. An emerging important area now focuses on [[supramolecular polymer]]s formed by [[Non-covalent interaction|non-covalent]] links. [[Polyisoprene]] of [[latex]] [[rubber]] is an example of a natural polymer, and the [[polystyrene]] of [[expanded polystyrene|styrofoam]] is an example of a synthetic polymer. In biological contexts, essentially all biological [[macromolecule]]s—i.e., proteins (polyamides), [[nucleic acid]]s (polynucleotides), and [[polysaccharide]]s—are purely polymeric, or are composed in large part of polymeric components.
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—e.g., isoprenylated or lipid-modified glycoproteins, where small lipidic molecules and [[oligosaccharide]] modifications occur on the polyamide backbone of the protein.<ref>{{cite journal |author1= Ten Feizi |author-link1=Ten Feizi |author2= Wengang Chai |title= Oligosaccharide microarrays to decipher the glyco code |journal= Nature Reviews Molecular Cell Biology |volume= 5 |pages= 582–588 |year= 2004 |doi= 10.1038/nrm1428 |pmid= 15232576 |issue= 7}}</ref>
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[[File:Polymer chain SPT.png|thumb|Cartoon schematic of polymer molecules]]