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Poly(N-isopropylacrylamide)

May 23, 2024

Poly(N-isopropylacrylamide) (variously abbreviated PNIPA, PNIPAM, PNIPAAm, NIPA, PNIPAA or PNIPAm) is a temperature-responsive polymer that was first synthesized in the 1950s.[2] It can be synthesized from N-isopropylacrylamide which is commercially available. It is synthesized via free-radical polymerization and is readily functionalized making it useful in a variety of applications.

Poly(N-isopropylacrylamide)
Identifiers
  • 25189-55-3
ChemSpider
  • none
  • 16637
  • DTXSID101011085
Properties[1]
(C6H11NO)n
Molar mass variable
Appearance white solid
Density 1.1 g/cm3
Melting point 96 °C (205 °F; 369 K)
Hazards[1]
NFPA 704 (fire diamond)
Health 0: Exposure under fire conditions would offer no hazard beyond that of ordinary combustible material. E.g. sodium chlorideFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
0
0
0
Safety data sheet (SDS) External MSDS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

PNIPA dissolves in water, however, when these solutions are heated in above their cloud point temperature, they undergo a reversible lower critical solution temperature (LCST) phase transition from a soluble hydrated state to an insoluble dehydrated state. Although it is widely believed that this phase transition occurs at 32 °C (90 °F),[3] the actual temperatures may differ 5 to 10 °C (or even more) depending on the polymer concentration,[3] molar mass of polymer chains, polymer dispersity as well as terminal moieties.[3][4] Furthermore, other molecules in the polymer solution, such as salts or proteins, can alter the cloud point temperature.[5][6]

Since PNIPA expels its liquid contents at a temperature near that of the human body, PNIPA copolymers have been investigated by many researchers for possible applications in tissue engineering[7][8] and controlled drug delivery.[9][10][11][12]

History edit

The synthesis of poly(N-isopropylacrylamide) began with the synthesis of the acrylamide monomer by Sprecht in 1956.[13] In 1957, Shearer patented the first application for what would be later identified as PNIPA for the use as a rodent repellent.[14] Early work was piqued by theoretical curiosity of the material properties of PNIPA. The first report of PNIPA came in 1968, which elucidated the unique thermal behavior in aqueous solutions.[15] The 1980s marked an explosion in interest in PNIPAs with the realization of potential applications due to its unique thermal behavior in aqueous solutions.[2]

Chemical and Physical Properties edit

PNIPA is one of the most studied thermosensitive hydrogels. In dilute solution, it undergoes a coil-to-globule transition.[16] PNIPA possesses an inverse solubility upon heating. It changes hydrophilicity and hydrophobicity abruptly at its LCST.[17] At lower temperatures PNIPA orders itself in solution in order to hydrogen bond with the already arranged water molecules. The water molecules must reorient around the nonpolar regions of PNIPA which results in a decreased entropy. At lower temperatures, such as room temperature, the negative enthalpy term ( ) from hydrogen bonding effects dominates the Gibbs free energy,

 
causing the PNIPA to absorb water and dissolve in solution. At higher temperatures, the entropy term ( ) dominates, causing the PNIPA to release water and phase separate which can be seen in the following demonstration.
Pictorial Depiction of the LCST Effect of PNIPA
  •  
    Aqueous solution of PNIPA before heating. The negative enthalpy of hydrogen bonding dominates and PNIPA is dissolved in the solution.
  •  
    The mixture after heating with a heat gun. The negative entropy of mixing dominates due to the increase in temperature and PNIPA phase separates from the water.
A demonstration of the heating of PNIPA to demonstrate the LCST effect.

Synthesis of Heat and pH Sensitive PNIPA edit

Homopolymerization[18]

The process of free radical polymerization of a single type of monomer, in this case, N-isopropylacrylamide, to form the polymer is known as a homopolymerization. The radical initiator azobisisobutyronitrile (AIBN) is commonly used in radical polymerizations.
 

Copolymerization

A free-radical polymerization of two different monomer results in a copolymerization. An advantage to a copolymerization includes fine tuning of the LCST.
 

Terpolymerization

A free-radical polymerization of three different monomer is known as a terpolymerization. Advantages to a terpolymerization may include enhancing multiple properties of the polymer including thermosensitivity, pH sensitivity or fine tuning of the LCST.
 

Cross-linked Hydrogel

The reaction scheme below is a terpolymerization to form a cross-linked hydrogel. The reactant ammonium persulfate (APS) is used in polymer chemistry as a strong oxidizing agent that is often used along with tetramethylethylenediamine (TMEDA) to catalyze the polymerization when making polyacrylamide gels.
 

Synthesis of Chain-End Functionalized PNIPA edit

PNIPA can be functionalized using chain transfer agents using a free radical polymerization. The three schemes below demonstrate functionalization using chain transfer agents (CTA), where one end of the polymer is the radical initiator and the other is a functionalized group. Functionalization of the polymer chain-end allows for the polymer to be used in many diverse settings and applications. Advantages to a functionalizing the chain-end may include enhancing multiple properties of the polymer including thermosensitivity, pH sensitivity or fine tuning of the LCST.[18]

(1)  

(2)  

(3)  

Applications edit

The versatility of PNIPA has led to finding uses in macroscopic gels, microgels,[19] membranes, sensors, biosensors, thin films,[20][21][22] tissue engineering, and drug delivery. The tendency of aqueous solutions of PNIPA to increase in viscosity in the presence of hydrophobic molecules has made it excellent for tertiary oil recovery.

As aqueous solutions of PNIPA have their lower critical solution temperature in temperatures around human body temperatures, these polymers can be dissolved in water at room temperature and administered into body.[23] However, upon the administration, these polymers phase-separate and form insoluble aggregates at site of administration (this process is called thermogelling).[23] When PNIPA is administered into muscles of mice, its half-life was approximately 48 days (Mw = 20 kg/mol) and 66 days (Mw = 32 kg/mol) and caused no local or systemic pathologies.[23] Such phase separated hydrogels can be used for local drug delivery applications.[24] The PNIPA can be placed in a solution of bioactive molecules, which allows the bioactive molecules to penetrate the PNIPA. The PNIPA can then be placed in vivo, where there is a rapid release of biomolecules due to the initial gel collapse and an ejection of the biomolecules into the surrounding media, followed by a slow release of biomolecules due to surface pore closure.[25]

PNIPA have also been used in pH-sensitive drug delivery systems. Some examples of these drug delivery systems may include the intestinal delivery of human calcitonin,[26] delivery of insulin,[26] and the delivery of ibuprofen.[27] When radiolabeled PNIPA copolymers with different molecular weights were intravenously injected to rats, it was found that the glomerular filtration threshold of the polymer was around 32 000 g/mol.[28]

PNIPA have been used in gel actuators, which convert external stimuli into mechanical motion.[29] Upon heating above the LCST, the hydrogel goes from hydrophilic to hydrophobic state.[30] This conversion results in an expulsion of water which causes a physical conformational change, creating a mechanical hinge movement.

Furthermore, PNIPA-based thin films can be applied as nano-switches featuring multiple distinct thin-film states, which is based on the cononsolvency effect.[31][32][33]

References edit

  1. ^ a b "Poly(N-isopropylacrylamide) Material Safety Data Sheet". sigmaadlrich.com. Retrieved January 24, 2014.
  2. ^ a b Schild, H.G. (1992). "Poly(N-isopropylacrylamide): Experiment, theory and application". Progress in Polymer Science. 17 (2): 163–249. doi:10.1016/0079-6700(92)90023-R.
  3. ^ a b c Halperin A, Kröger M, Winnik FM (2015). "Poly(N-isopropylacrylamide) Phase Diagrams: Fifty Years of Research". Angew Chem Int Ed Engl. 54 (51): 15342–67. doi:10.1002/anie.201506663. PMID 26612195.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  4. ^ Aseyev, Vladimir; Tenhu, Heikki; Winnik, Françoise M. (2010). "Non-ionic Thermoresponsive Polymers in Water". Advances in Polymer Science. Vol. 242. Berlin, Heidelberg: Springer Berlin Heidelberg. pp. 29–89. doi:10.1007/12_2010_57. ISBN 978-3-642-22296-2. ISSN 0065-3195.
  5. ^ Kolouchová, Kristýna; Lobaz, Volodymyr; Beneš, Hynek; et al. (2021). "Thermoresponsive properties of polyacrylamides in physiological solutions". Polymer Chemistry. 12 (35). Royal Society of Chemistry (RSC): 5077–5084. doi:10.1039/d1py00843a. hdl:1854/LU-8724379. ISSN 1759-9954. S2CID 238937814.
  6. ^ Zhang, Yanjie; Furyk, Steven; Sagle, Laura B.; et al. (2007). "Effects of Hofmeister Anions on the LCST of PNIPAM as a Function of Molecular Weight†". The Journal of Physical Chemistry C. 111 (25). American Chemical Society (ACS): 8916–8924. doi:10.1021/jp0690603. ISSN 1932-7447. PMC 2553222. PMID 18820735.
  7. ^ von Recum, H. A.; Kikuchi, A.; Okuhara, M.; Sakurai, Y.; Okano, T.; Kim, S. W. (1998). "Retinal pigmented epithelium cultures on thermally responsive polymer porous substrates". Journal of Biomaterials Science, Polymer Edition. 9 (11): 1241–1253. doi:10.1163/156856298X00758. PMID 9860183.
  8. ^ Lee, EL.; von Recum, HA (2010). "Cell culture platform with mechanical conditioning and nondamaging cellular detachment". J Biomed Mater Res A. 93 (2): 411–8. doi:10.1002/jbm.a.32754. PMID 20358641. S2CID 23022529.
  9. ^ Chung, J. E.; Yokoyama, M.; Yamato, M.; et al. (1999). "Thermo-responsive drug delivery from polymeric micelles constructed using block copolymers of poly(N-isopropylacrylamide) and poly(butylmethacrylate)". Journal of Controlled Release. 62 (1–2): 115–127. doi:10.1016/S0168-3659(99)00029-2. PMID 10518643.
  10. ^ Yan, Hu; Tsujii, Kaoru (2005). "Potential application of poly(N-isopropylacrylamide) gel containing polymeric micelles to drug delivery systems". Colloids and Surfaces B: Biointerfaces. 46 (3): 142–146. doi:10.1016/j.colsurfb.2005.10.007. hdl:2115/1381. PMID 16300934. S2CID 31084515.
  11. ^ Filipe E. Antunes; Luigi Gentile; Lorena Tavano; Cesare Oliviero Rossi (2009). "Rheological characterization of the thermal gelation of poly(N-isopropylacrylamide) and poly(N-isopropylacrylamide)co-Acrylic Acid". Applied Rheology. doi:10.3933/ApplRheol-19-42064.
  12. ^ Dang, Steven; Brady, John; Rel, Ryle; Surineni, Sreenidhi; O'Shaughnessy, Conor; McGorty, Ryan (August 2, 2021). "Core-shell droplets and microcapsules formed through liquid-liquid phase separation of a colloid-polymer mixture". arXiv.org. Retrieved March 17, 2024.
  13. ^ US 2773063 
  14. ^ US 2790744 
  15. ^ M. Heskins; J. E. Guillet (1968). "Solution Properties of Poly(N-isopropylacrylamide)". Journal of Macromolecular Science, Part A. 2 (8): 1441–1455. doi:10.1080/10601326808051910.
  16. ^ Wu, C; Wang, X (1998). (PDF). Physical Review Letters. 80 (18): 4092–4094. Bibcode:1998PhRvL..80.4092W. doi:10.1103/PhysRevLett.80.4092. Archived from the original (PDF) on July 21, 2011. Retrieved September 25, 2010.
  17. ^ Somasundaran, Ponisseril (2004). Encyclopedia of Surface and Colloid Science. Taylor & Francis. ISBN 978-0-8247-2154-1. Retrieved February 13, 2014.
  18. ^ a b "Designing temperature and pH sensitive NIPAM based polymers". sigmaadlrich.com. Retrieved January 25, 2014.
  19. ^ Widmann, Tobias; Kreuzer, Lucas P.; Hohn, Nuri; et al. (December 10, 2019). "Hydration and Solvent Exchange Induced Swelling and Deswelling of Homogeneous Poly(N-isopropylacrylamide) Microgel Thin Films". Langmuir. 35 (49): 16341–16352. doi:10.1021/acs.langmuir.9b03104. ISSN 0743-7463. PMID 31714092. S2CID 207940427.
  20. ^ Kreuzer, Lucas P.; Widmann, Tobias; Hohn, Nuri; et al. (May 14, 2019). "Swelling and Exchange Behavior of Poly(sulfobetaine)-Based Block Copolymer Thin Films". Macromolecules. 52 (9): 3486–3498. Bibcode:2019MaMol..52.3486K. doi:10.1021/acs.macromol.9b00443. ISSN 0024-9297. S2CID 155174181.
  21. ^ Kreuzer, Lucas P.; Widmann, Tobias; Bießmann, Lorenz; et al. (April 28, 2020). "Phase Transition Kinetics of Doubly Thermoresponsive Poly(sulfobetaine)-Based Diblock Copolymer Thin Films". Macromolecules. 53 (8): 2841–2855. Bibcode:2020MaMol..53.2841K. doi:10.1021/acs.macromol.0c00046. ISSN 0024-9297. S2CID 216346530.
  22. ^ Kreuzer, Lucas P.; Widmann, Tobias; Aldosari, Nawarah; et al. (October 27, 2020). "Cyclic Water Storage Behavior of Doubly Thermoresponsive Poly(sulfobetaine)-Based Diblock Copolymer Thin Films". Macromolecules. 53 (20): 9108–9121. Bibcode:2020MaMol..53.9108K. doi:10.1021/acs.macromol.0c01335. ISSN 0024-9297. S2CID 226323489.
  23. ^ a b c Groborz, Ondřej; Kolouchová, Kristýna; Pankrác, Jan; et al. (2022). "Pharmacokinetics of Intramuscularly Administered Thermoresponsive Polymers". Advanced Healthcare Materials. 11 (22). doi:10.1002/adhm.202201344. ISSN 2192-2640. PMID 36153823.
  24. ^ A. T. Okano; Y. H. Bae; H. Jacobs; S. W. Kim (1990). "Thermally on-off switching polymers for drug permeation and release". Journal of Controlled Release. 11 (1–3): 255–265. doi:10.1016/0168-3659(90)90138-j.
  25. ^ Allan S. Hoffman; Ali Afrassiabi; Liang Chang Dong (1986). "Thermally reversible hydrogels: II. Delivery and selective removal of substances from aqueous solutions". Journal of Controlled Release. 4 (3): 213–222. doi:10.1016/0168-3659(86)90005-2.
  26. ^ a b Schmaljohann, Dirk (2006). "Thermo- and pH-responsive polymers in drug delivery" (PDF). Advanced Drug Delivery Reviews. 58 (15). Elsevier: 1655–70. doi:10.1016/j.addr.2006.09.020. PMID 17125884. Retrieved March 13, 2014.
  27. ^ Zhu, Senmin; Zhou, Zhengyang; Zhang, Di (March 15, 2007). "Grafting of thermo-responsive polymer inside mesoporous silica with large pore size using ATRP and investigation of its use in drug release". J. Mater. Chem. 17 (23): 2428–2433. doi:10.1039/b618834f.
  28. ^ Bertrand, N.; Fleischer, J.G.; Wasan, K.M.; et al. (2009). "Pharmacokinetics and biodistribution of N-isopropylacrylamide copolymers for the design of pH-sensitive liposomes". Biomaterials. 30 (13): 2598–2605. doi:10.1016/j.biomaterials.2008.12.082. PMID 19176241.
  29. ^ Chandorkar, Yashoda; Castro Nava, Arturo; Schweizerhof, Sjören; et al. (September 6, 2019). "Cellular responses to beating hydrogels to investigate mechanotransduction". Nature Communications. 10 (1). Springer Science and Business Media LLC: 4027. Bibcode:2019NatCo..10.4027C. doi:10.1038/s41467-019-11475-4. ISSN 2041-1723. PMC 6731269. PMID 31492837.
  30. ^ Xiaobo Zhang; Cary L. Pint; Min Hyung Lee; et al. (2011). "Optically- and Thermally-Responsive Programmable Materials Based on Carbon Nanotube-Hydrogel Polymer Composites". Nano Letters. 11 (8): 3239–3244. Bibcode:2011NanoL..11.3239Z. doi:10.1021/nl201503e. PMID 21736337. S2CID 14317595.
  31. ^ Kreuzer, Lucas P.; Geiger, Christina; Widmann, Tobias; et al. (August 10, 2021). "Solvation Behavior of Poly(sulfobetaine)-Based Diblock Copolymer Thin Films in Mixed Water/Methanol Vapors". Macromolecules. 54 (15): 7147–7159. Bibcode:2021MaMol..54.7147K. doi:10.1021/acs.macromol.1c01179. ISSN 0024-9297. S2CID 237724968.
  32. ^ Kreuzer, Lucas P.; Lindenmeir, Christoph; Geiger, Christina; et al. (February 9, 2021). "Poly(sulfobetaine) versus Poly(N-isopropylmethacrylamide): Co-Nonsolvency-Type Behavior of Thin Films in a Water/Methanol Atmosphere". Macromolecules. 54 (3): 1548–1556. Bibcode:2021MaMol..54.1548K. doi:10.1021/acs.macromol.0c02281. ISSN 0024-9297. S2CID 234184714.
  33. ^ Geiger, Christina; Reitenbach, Julija; Henschel, Cristiane; et al. (November 2021). "Ternary Nanoswitches Realized with Multiresponsive PMMA‐ b ‐PNIPMAM Films in Mixed Water/Acetone Vapor Atmospheres". Advanced Engineering Materials. 23 (11): 2100191. doi:10.1002/adem.202100191. ISSN 1438-1656. S2CID 235560292.
 
Wikimedia Commons has media related to Poly(N-isopropylacrylamide).

May 23, 2024
poly, isopropylacrylamide, variously, abbreviated, pnipa, pnipam, pnipaam, nipa, pnipaa, pnipam, temperature, responsive, polymer, that, first, synthesized, 1950s, synthesized, from, isopropylacrylamide, which, commercially, available, synthesized, free, radic. Poly N isopropylacrylamide variously abbreviated PNIPA PNIPAM PNIPAAm NIPA PNIPAA or PNIPAm is a temperature responsive polymer that was first synthesized in the 1950s 2 It can be synthesized from N isopropylacrylamide which is commercially available It is synthesized via free radical polymerization and is readily functionalized making it useful in a variety of applications Poly N isopropylacrylamide Identifiers CAS Number 25189 55 3 ChemSpider none PubChem CID 16637 CompTox Dashboard EPA DTXSID101011085 Properties 1 Chemical formula C6H11NO n Molar mass variable Appearance white solid Density 1 1 g cm3 Melting point 96 C 205 F 369 K Hazards 1 NFPA 704 fire diamond 000 Safety data sheet SDS External MSDS Except where otherwise noted data are given for materials in their standard state at 25 C 77 F 100 kPa Infobox references PNIPA dissolves in water however when these solutions are heated in above their cloud point temperature they undergo a reversible lower critical solution temperature LCST phase transition from a soluble hydrated state to an insoluble dehydrated state Although it is widely believed that this phase transition occurs at 32 C 90 F 3 the actual temperatures may differ 5 to 10 C or even more depending on the polymer concentration 3 molar mass of polymer chains polymer dispersity as well as terminal moieties 3 4 Furthermore other molecules in the polymer solution such as salts or proteins can alter the cloud point temperature 5 6 Since PNIPA expels its liquid contents at a temperature near that of the human body PNIPA copolymers have been investigated by many researchers for possible applications in tissue engineering 7 8 and controlled drug delivery 9 10 11 12 Contents 1 History 2 Chemical and Physical Properties 3 Synthesis of Heat and pH Sensitive PNIPA 4 Synthesis of Chain End Functionalized PNIPA 5 Applications 6 ReferencesHistory editThe synthesis of poly N isopropylacrylamide began with the synthesis of the acrylamide monomer by Sprecht in 1956 13 In 1957 Shearer patented the first application for what would be later identified as PNIPA for the use as a rodent repellent 14 Early work was piqued by theoretical curiosity of the material properties of PNIPA The first report of PNIPA came in 1968 which elucidated the unique thermal behavior in aqueous solutions 15 The 1980s marked an explosion in interest in PNIPAs with the realization of potential applications due to its unique thermal behavior in aqueous solutions 2 Chemical and Physical Properties editPNIPA is one of the most studied thermosensitive hydrogels In dilute solution it undergoes a coil to globule transition 16 PNIPA possesses an inverse solubility upon heating It changes hydrophilicity and hydrophobicity abruptly at its LCST 17 At lower temperatures PNIPA orders itself in solution in order to hydrogen bond with the already arranged water molecules The water molecules must reorient around the nonpolar regions of PNIPA which results in a decreased entropy At lower temperatures such as room temperature the negative enthalpy term D H displaystyle Delta H nbsp from hydrogen bonding effects dominates the Gibbs free energy D G D H T D S displaystyle Delta G Delta H T Delta S nbsp causing the PNIPA to absorb water and dissolve in solution At higher temperatures the entropy term D S displaystyle Delta S nbsp dominates causing the PNIPA to release water and phase separate which can be seen in the following demonstration Pictorial Depiction of the LCST Effect of PNIPA nbsp Aqueous solution of PNIPA before heating The negative enthalpy of hydrogen bonding dominates and PNIPA is dissolved in the solution nbsp The mixture after heating with a heat gun The negative entropy of mixing dominates due to the increase in temperature and PNIPA phase separates from the water source source source source source source source A demonstration of the heating of PNIPA to demonstrate the LCST effect Synthesis of Heat and pH Sensitive PNIPA editHomopolymerization 18 The process of free radical polymerization of a single type of monomer in this case N isopropylacrylamide to form the polymer is known as a homopolymerization The radical initiator azobisisobutyronitrile AIBN is commonly used in radical polymerizations nbsp Copolymerization A free radical polymerization of two different monomer results in a copolymerization An advantage to a copolymerization includes fine tuning of the LCST nbsp Terpolymerization A free radical polymerization of three different monomer is known as a terpolymerization Advantages to a terpolymerization may include enhancing multiple properties of the polymer including thermosensitivity pH sensitivity or fine tuning of the LCST nbsp Cross linked Hydrogel The reaction scheme below is a terpolymerization to form a cross linked hydrogel The reactant ammonium persulfate APS is used in polymer chemistry as a strong oxidizing agent that is often used along with tetramethylethylenediamine TMEDA to catalyze the polymerization when making polyacrylamide gels nbsp Synthesis of Chain End Functionalized PNIPA editPNIPA can be functionalized using chain transfer agents using a free radical polymerization The three schemes below demonstrate functionalization using chain transfer agents CTA where one end of the polymer is the radical initiator and the other is a functionalized group Functionalization of the polymer chain end allows for the polymer to be used in many diverse settings and applications Advantages to a functionalizing the chain end may include enhancing multiple properties of the polymer including thermosensitivity pH sensitivity or fine tuning of the LCST 18 1 nbsp 2 nbsp 3 nbsp Applications editThe versatility of PNIPA has led to finding uses in macroscopic gels microgels 19 membranes sensors biosensors thin films 20 21 22 tissue engineering and drug delivery The tendency of aqueous solutions of PNIPA to increase in viscosity in the presence of hydrophobic molecules has made it excellent for tertiary oil recovery As aqueous solutions of PNIPA have their lower critical solution temperature in temperatures around human body temperatures these polymers can be dissolved in water at room temperature and administered into body 23 However upon the administration these polymers phase separate and form insoluble aggregates at site of administration this process is called thermogelling 23 When PNIPA is administered into muscles of mice its half life was approximately 48 days Mw 20 kg mol and 66 days Mw 32 kg mol and caused no local or systemic pathologies 23 Such phase separated hydrogels can be used for local drug delivery applications 24 The PNIPA can be placed in a solution of bioactive molecules which allows the bioactive molecules to penetrate the PNIPA The PNIPA can then be placed in vivo where there is a rapid release of biomolecules due to the initial gel collapse and an ejection of the biomolecules into the surrounding media followed by a slow release of biomolecules due to surface pore closure 25 PNIPA have also been used in pH sensitive drug delivery systems Some examples of these drug delivery systems may include the intestinal delivery of human calcitonin 26 delivery of insulin 26 and the delivery of ibuprofen 27 When radiolabeled PNIPA copolymers with different molecular weights were intravenously injected to rats it was found that the glomerular filtration threshold of the polymer was around 32 000 g mol 28 PNIPA have been used in gel actuators which convert external stimuli into mechanical motion 29 Upon heating above the LCST the hydrogel goes from hydrophilic to hydrophobic state 30 This conversion results in an expulsion of water which causes a physical conformational change creating a mechanical hinge movement Furthermore PNIPA based thin films can be applied as nano switches featuring multiple distinct thin film states which is based on the cononsolvency effect 31 32 33 References edit a b Poly N isopropylacrylamide Material Safety Data Sheet sigmaadlrich com Retrieved January 24 2014 a b Schild H G 1992 Poly N isopropylacrylamide Experiment theory and application Progress in Polymer Science 17 2 163 249 doi 10 1016 0079 6700 92 90023 R a b c Halperin A Kroger M Winnik FM 2015 Poly N isopropylacrylamide Phase Diagrams Fifty Years of Research Angew Chem Int Ed Engl 54 51 15342 67 doi 10 1002 anie 201506663 PMID 26612195 a href Template Cite journal html title Template Cite journal cite journal a CS1 maint multiple names authors list link Aseyev Vladimir Tenhu Heikki Winnik Francoise M 2010 Non ionic Thermoresponsive Polymers in Water Advances in Polymer Science Vol 242 Berlin Heidelberg Springer Berlin Heidelberg pp 29 89 doi 10 1007 12 2010 57 ISBN 978 3 642 22296 2 ISSN 0065 3195 Kolouchova Kristyna Lobaz Volodymyr Benes Hynek et al 2021 Thermoresponsive properties of polyacrylamides in physiological solutions Polymer Chemistry 12 35 Royal Society of Chemistry RSC 5077 5084 doi 10 1039 d1py00843a hdl 1854 LU 8724379 ISSN 1759 9954 S2CID 238937814 Zhang Yanjie Furyk Steven Sagle Laura B et al 2007 Effects of Hofmeister Anions on the LCST of PNIPAM as a Function of Molecular Weight The Journal of Physical Chemistry C 111 25 American Chemical Society ACS 8916 8924 doi 10 1021 jp0690603 ISSN 1932 7447 PMC 2553222 PMID 18820735 von Recum H A Kikuchi A Okuhara M Sakurai Y Okano T Kim S W 1998 Retinal pigmented epithelium cultures on thermally responsive polymer porous substrates Journal of Biomaterials Science Polymer Edition 9 11 1241 1253 doi 10 1163 156856298X00758 PMID 9860183 Lee EL von Recum HA 2010 Cell culture platform with mechanical conditioning and nondamaging cellular detachment J Biomed Mater Res A 93 2 411 8 doi 10 1002 jbm a 32754 PMID 20358641 S2CID 23022529 Chung J E Yokoyama M Yamato M et al 1999 Thermo responsive drug delivery from polymeric micelles constructed using block copolymers of poly N isopropylacrylamide and poly butylmethacrylate Journal of Controlled Release 62 1 2 115 127 doi 10 1016 S0168 3659 99 00029 2 PMID 10518643 Yan Hu Tsujii Kaoru 2005 Potential application of poly N isopropylacrylamide gel containing polymeric micelles to drug delivery systems Colloids and Surfaces B Biointerfaces 46 3 142 146 doi 10 1016 j colsurfb 2005 10 007 hdl 2115 1381 PMID 16300934 S2CID 31084515 Filipe E Antunes Luigi Gentile Lorena Tavano Cesare Oliviero Rossi 2009 Rheological characterization of the thermal gelation of poly N isopropylacrylamide and poly N isopropylacrylamide co Acrylic Acid Applied Rheology doi 10 3933 ApplRheol 19 42064 Dang Steven Brady John Rel Ryle Surineni Sreenidhi O Shaughnessy Conor McGorty Ryan August 2 2021 Core shell droplets and microcapsules formed through liquid liquid phase separation of a colloid polymer mixture arXiv org Retrieved March 17 2024 US 2773063 US 2790744 M Heskins J E Guillet 1968 Solution Properties of Poly N isopropylacrylamide Journal of Macromolecular Science Part A 2 8 1441 1455 doi 10 1080 10601326808051910 Wu C Wang X 1998 Globule to Coil Transition of a Single Homopolymer Chain in Solution PDF Physical Review Letters 80 18 4092 4094 Bibcode 1998PhRvL 80 4092W doi 10 1103 PhysRevLett 80 4092 Archived from the original PDF on July 21 2011 Retrieved September 25 2010 Somasundaran Ponisseril 2004 Encyclopedia of Surface and Colloid Science Taylor amp Francis ISBN 978 0 8247 2154 1 Retrieved February 13 2014 a b Designing temperature and pH sensitive NIPAM based polymers sigmaadlrich com Retrieved January 25 2014 Widmann Tobias Kreuzer Lucas P Hohn Nuri et al December 10 2019 Hydration and Solvent Exchange Induced Swelling and Deswelling of Homogeneous Poly N isopropylacrylamide Microgel Thin Films Langmuir 35 49 16341 16352 doi 10 1021 acs langmuir 9b03104 ISSN 0743 7463 PMID 31714092 S2CID 207940427 Kreuzer Lucas P Widmann Tobias Hohn Nuri et al May 14 2019 Swelling and Exchange Behavior of Poly sulfobetaine Based Block Copolymer Thin Films Macromolecules 52 9 3486 3498 Bibcode 2019MaMol 52 3486K doi 10 1021 acs macromol 9b00443 ISSN 0024 9297 S2CID 155174181 Kreuzer Lucas P Widmann Tobias Biessmann Lorenz et al April 28 2020 Phase Transition Kinetics of Doubly Thermoresponsive Poly sulfobetaine Based Diblock Copolymer Thin Films Macromolecules 53 8 2841 2855 Bibcode 2020MaMol 53 2841K doi 10 1021 acs macromol 0c00046 ISSN 0024 9297 S2CID 216346530 Kreuzer Lucas P Widmann Tobias Aldosari Nawarah et al October 27 2020 Cyclic Water Storage Behavior of Doubly Thermoresponsive Poly sulfobetaine Based Diblock Copolymer Thin Films Macromolecules 53 20 9108 9121 Bibcode 2020MaMol 53 9108K doi 10 1021 acs macromol 0c01335 ISSN 0024 9297 S2CID 226323489 a b c Groborz Ondrej Kolouchova Kristyna Pankrac Jan et al 2022 Pharmacokinetics of Intramuscularly Administered Thermoresponsive Polymers Advanced Healthcare Materials 11 22 doi 10 1002 adhm 202201344 ISSN 2192 2640 PMID 36153823 A T Okano Y H Bae H Jacobs S W Kim 1990 Thermally on off switching polymers for drug permeation and release Journal of Controlled Release 11 1 3 255 265 doi 10 1016 0168 3659 90 90138 j Allan S Hoffman Ali Afrassiabi Liang Chang Dong 1986 Thermally reversible hydrogels II Delivery and selective removal of substances from aqueous solutions Journal of Controlled Release 4 3 213 222 doi 10 1016 0168 3659 86 90005 2 a b Schmaljohann Dirk 2006 Thermo and pH responsive polymers in drug delivery PDF Advanced Drug Delivery Reviews 58 15 Elsevier 1655 70 doi 10 1016 j addr 2006 09 020 PMID 17125884 Retrieved March 13 2014 Zhu Senmin Zhou Zhengyang Zhang Di March 15 2007 Grafting of thermo responsive polymer inside mesoporous silica with large pore size using ATRP and investigation of its use in drug release J Mater Chem 17 23 2428 2433 doi 10 1039 b618834f Bertrand N Fleischer J G Wasan K M et al 2009 Pharmacokinetics and biodistribution of N isopropylacrylamide copolymers for the design of pH sensitive liposomes Biomaterials 30 13 2598 2605 doi 10 1016 j biomaterials 2008 12 082 PMID 19176241 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isopropylmethacrylamide Co Nonsolvency Type Behavior of Thin Films in a Water Methanol Atmosphere Macromolecules 54 3 1548 1556 Bibcode 2021MaMol 54 1548K doi 10 1021 acs macromol 0c02281 ISSN 0024 9297 S2CID 234184714 Geiger Christina Reitenbach Julija Henschel Cristiane et al November 2021 Ternary Nanoswitches Realized with Multiresponsive PMMA b PNIPMAM Films in Mixed Water Acetone Vapor Atmospheres Advanced Engineering Materials 23 11 2100191 doi 10 1002 adem 202100191 ISSN 1438 1656 S2CID 235560292 nbsp Wikimedia Commons has media related to Poly N isopropylacrylamide Retrieved from https en wikipedia org w index php title Poly N isopropylacrylamide amp oldid 1214108393, wikipedia, wiki, book, books, library,

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