Editing Copolymer (section)

== Characterization ==
[[Characterization (materials science)|Characterization]] techniques for copolymers are similar to those for other polymeric materials. These techniques can be used to determine the average [[Molecular mass|molecular weight]], molecular size, chemical composition, molecular [[Homogeneity and heterogeneity|homogeneity]], and physiochemical properties of the material.<ref name=":0" /> However, given that copolymers are made of base polymer components with heterogeneous properties, this may require multiple characterization techniques to accurately characterize these copolymers.<ref>{{Cite journal |last1=Rowland |first1=Steven M. |last2=Striegel |first2=André M. |date=2012-06-05 |title=Characterization of Copolymers and Blends by Quintuple-Detector Size-Exclusion Chromatography |url=https://pubs.acs.org/doi/abs/10.1021/ac3003775 |journal=Analytical Chemistry |language=en |volume=84 |issue=11 |pages=4812–4820 |doi=10.1021/ac3003775 |pmid=22591263 |issn=0003-2700}}</ref>

Spectroscopic techniques, such as [[nuclear magnetic resonance spectroscopy]], [[infrared spectroscopy]], and [[Ultraviolet–visible spectroscopy|UV spectroscopy]], are often used to identify the molecular structure and chemical composition of copolymers. In particular, NMR can indicate the [[tacticity]] and configuration of polymeric chains while IR can identify functional groups attached to the copolymer.

Scattering techniques, such as [[static light scattering]], [[dynamic light scattering]], and [[small-angle neutron scattering]], can determine the molecular size and weight of the synthesized copolymer. Static light scattering and dynamic light scattering use light to determine the average molecular weight and behavior of the copolymer in solution whereas small-angle neutron scattering uses neutrons to determine the molecular weight and chain length. Additionally, x-ray scattering techniques, such as [[small-angle X-ray scattering]] (SAXS) can help determine the nanometer morphology and characteristic feature size of a microphase-separated block-copolymer or suspended micelles. <ref>{{Cite journal |last1=Hu |first1=Hanqiong |last2=Gopinadhan|first2=Manesh|last3=Osuji|first3=Chinedum O.  |date=2014-03-21 |title=Directed self-assembly of block copolymers: a tutorial review of strategies for enabling nanotechnology with soft matter|url=https://pubs.rsc.org/en/content/articlelanding/2014/sm/c3sm52607k |journal=Soft Matter |language=en |volume=22 |issue=10 |pages=3867-3889 |doi=10.1039/C3SM52607K}}</ref>

[[Differential scanning calorimetry]] is a thermoanalytical technique used to determine the thermal events of the copolymer as a function of temperature.<ref>{{Cite book |last=Skoog |first=Douglas A. |url=https://www.worldcat.org/oclc/37866092 |title=Principles of instrumental analysis |date=1998 |publisher=Saunders College Pub. |others=F. James Holler, Timothy A. Nieman |isbn=0-03-002078-6 |edition=5th |location=Philadelphia |oclc=37866092}}</ref> It can indicate when the copolymer is undergoing a [[phase transition]], such as crystallization or melting, by measuring the heat flow required to maintain the material and a reference at a constantly increasing temperature.

[[Thermogravimetric analysis]] is another thermoanalytical technique used to access the thermal stability of the copolymer as a function of temperature. This provides information on any changes to the physicochemical properties, such as phase transitions, thermal decompositions, and redox reactions.<ref>{{Cite journal |last1=Coats |first1=A. W. |last2=Redfern |first2=J. P. |date=1963-01-01 |title=Thermogravimetric analysis. A review |url=https://pubs.rsc.org/en/content/articlelanding/1963/an/an9638800906 |journal=Analyst |language=en |volume=88 |issue=1053 |pages=906–924 |doi=10.1039/AN9638800906 |bibcode=1963Ana....88..906C |issn=1364-5528}}</ref>

[[Size-exclusion chromatography]] can separate copolymers with different molecular weights based on their hydrodynamic volume.<ref>{{Cite book |last=Yamakawa |first=Hiromi |url=https://www.worldcat.org/oclc/159244 |title=Modern theory of polymer solutions. |date=1971 |publisher=Harper & Row |isbn=0-06-047309-6 |location=New York |oclc=159244}}</ref> From there, the molecular weight can be determined by deriving the relationship from its hydrodynamic volume. Larger copolymers tend to elute first as they do not interact with the column as much. The collected material is commonly detected by light scattering methods, a refractometer, or a viscometer to determine the concentration of the eluted copolymer.