Triply-Responsive Poly(N,N-Dimethylaminoethyl Mathacrylate) with an Azobenzene Moiety

2010 ◽  
Vol 663-665 ◽  
pp. 1049-1052
Author(s):  
Xin De Tang ◽  
Xin Wang ◽  
Yuan Yuan Dou
Keyword(s):  
Uv Light ◽  
Aqueous Media ◽  
Gel Permeation Chromatography ◽  
Terminal Group ◽  
Light Irradiation ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Molecular Weights ◽  
Azobenzene Moiety ◽  
Azobenzene Group

A serious of triply-responsive poly(N,N-dimethylaminoethyl methacrylate) (PMAEMA) containing an azobenzene group as the terminal group were synthesized by atom transfer radical polymerization (ATRP). The ATRP process of DMAEMA was initiated by an azobenzene derivative substituted with a 2-bromoisobutyryl group (Azo-Br) using CuCl/Me6TREN as catalyst and the mixture of DMA and H2O (v/v = 3:1) as solvent. The molecular weights and their distributions of the resulting homopolymers (Azo-PDMAEMA) were characterized by gel permeation chromatography (GPC). The polymers are soluble in aqueous media and exhibit a lower critical solution temperature (LCST) that alternated reversibly in response to pH and photoisomerization of the terminal azobenzene moiety. It was found that the LCST increased as pH decreased in the range of testing. Under UV light irradiation, the trans-to-cis photoisomerization of the azobenzene moiety resulted in a higher LCST, while it recovered under visible light irradiation.

Color Transition Properties of Water Dispersible Polydiacetylene Particles Conjugated with the Thermosensitive Polymer

2017 ◽  
Vol 863 ◽  
pp. 38-43
Author(s):  
Izumi Harano ◽  
Chigusa Okano ◽  
Yuriko Takayama ◽  
Eri Nasuno ◽  
Ken-ichi Iimura ◽  
...  
Keyword(s):  
Color Change ◽  
Uv Light ◽  
Aqueous Media ◽  
Polymerization Reaction ◽  
Solution Temperature ◽  
Thermosensitive Polymer ◽  
Critical Solution Temperature ◽  
Color Transition ◽  
Water Dispersible ◽  
System A

An assembly of diacetylene molecules is necessary to progress a topochemical reaction as UV-irradiated polymerization. In this study, we attempt to regularly assemble 10, 12- pentacosadiynoic acid (PCDA) by freezing the solution, followed by lyophilization. Dried PCDA assembly was easily dispersed in aqueous solution by sonication. Irradiation of UV light can promote polymerization reaction of PCDA judging from a color change of the solution into blue. A color transition of the polyPCDA-dispersed solution from blue to red was observed at approximately 56°C due to distortion of its π-conjugated system. A color transition temperature could be controlled by hybridization with thermosensitive hydroxypropyl cellulose, of which lower critical solution temperature appears around 38-39°C. By synchronizing to coli-globule transition of HPC in aqueous media, blue-red transition response of water-dispersed polyPCDA could be induced by changing conformation of surrounded polymer.

Novel Polymerization of Myrcene in Aqueous Media via Cyclodextrin-Complexes

e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
SooWhan Choi ◽  
Helmut Ritter
Keyword(s):  
Room Temperature ◽  
Aqueous Media ◽  
Gel Permeation Chromatography ◽  
Solution Temperature ◽  
Cyclodextrin Complexes ◽  
Scanning Calorimetry ◽  
Critical Solution Temperature ◽  
Gel Permeation ◽  
Redox Initiator ◽  
C Nmr

AbstractFree radical homopolymerization with methylated β-cyclodextrin (CD) complexed myrcene (1a) and co-polymerization of 1a with diethyl fumarate (2a) and styrene (3a) were carried out using redox initiator in aqueous media at room temperature. Control experiments showed that uncomplexed myrcene (1) does not polymerize under similar conditions in water. The polymers obtained were characterized by means of 1H/13C-NMR spectroscopy, differential scanning calorimetry (DSC) and gel-permeation chromatography (GPC). Additionally, Nisopropylacrylamide containing copolymer was synthesized in water using redox initiator and the lower critical solution temperature (LCST) behaviour was studied.

scholarly journals EXTRACTION AND REEXTRACTION OF HISTIDINE AND RIBOFLAVIN BY N-VINYLCAPROLACTAME COPOLYMERS WITH 1-VINYL- AND 1-METHACRYLOYL-3,5-DIMETHYLPYROZOLE

2018 ◽  
Vol 59 (7) ◽  
pp. 55
Author(s):  
Maria S. Lavlinskaya ◽  
Gennadiy V. Shatalov ◽  
Nadezhda Ya. Mokshina ◽  
Oksana A. Pakhomova ◽  
Vyacheslav A. Kuznetsov
Keyword(s):  
Free Radical ◽  
Uv Spectroscopy ◽  
Aqueous Media ◽  
Radical Copolymerization ◽  
Water Soluble ◽  
Solution Temperature ◽  
Free Radical Copolymerization ◽  
Critical Solution Temperature ◽  
Two Phases ◽  
Degree Of Extraction

Copolymers of N-vinylcaprolactam (VC) with 1-vinyl-3,5-dimethylpyrazole (VDMP) and 1-methacryloyl-3,5-dimethylpyrazole (MDMP) were synthesized by free radical copolymerization  in dioxane with azodiisobutironitrole as initiator. Both water-soluble and water-insoluble copolymers were obtained. The copolymers compositions were determined by FTIR and UV-spectroscopy. The copolymerization constants were calculated and they were: for VC (М1)–VDMP, r1 = 0.65 ± 0.03, r2 = 0.43 ± 0.03; for VC (М1)–MDMP, r1 = 0.79 ± 0.04, r2 = 0.21 ± 0.02. These values show that VC (М1) exhibits somewhat higher activity compared to М2 and that the tendency toward alternation of comonomer units is more pronounced in VC–MDMP copolymers (r1r2 = 0.17) compared to VC–VDMP copolymers (r1r2 = 0.27). It was found that VC–VDMP copolymers are water-soluble at VC content higher than 75 mol %, and VC–MDMP copolymers at VC content higher than 88 mol %. The water-soluble copolymers based on VC have lower critical solution temperature. Their values are in range of 54-69 °C. Two-phases water-salts systems based on synthesized water-soludle thermoresponsive copolymers are proposed for histidine and riboflavin (re)extraction in aqueous media. It was found that extraction systems based on VC-VDMP copolymers are more efficient then VC-MDMP systems. Degree of extraction for both substances in a case of VC-VDMP copolymers achieved 96%. Reextraction carried out by thermoprecipitation of VC (co)polymers. It was shown that reextraction is more efficient at pH 7.6 and its degree achieved 61.7 % for histidine.

scholarly journals Synthesis, Structure, Hydrodynamics and Thermoresponsiveness of Graft Copolymer with Aromatic Polyester Backbone at Poly(2-isopropyl-2-oxazoline) Side Chains

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2643 ◽  
Author(s):  
Elena Tarabukina ◽  
Emil Fatullaev ◽  
Anna Krasova ◽  
Mikhail Kurlykin ◽  
Andrey Tenkovtsev ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Graft Copolymer ◽  
Graft Copolymers ◽  
Linear Chain ◽  
Terminal Group ◽  
Solution Temperature ◽  
Side Chains ◽  
Critical Solution Temperature ◽  
Copolymer Solution ◽  
Aromatic Polyester

New thermoresponsive graft copolymers with an aromatic polyester backbone and poly(2-isopropyl-2-oxazoline) (PiPrOx) side chains are synthesized and characterized by NMR and GPC. The grafting density of side chains is 0.49. The molar masses of the graft-copolymer, its backbone, side chains, and the modeling poly-2-isopropyl-2-oxaziline are 74,000, 19,000, 4300, and 16,600 g·mol−1, respectively. Their conformational properties in nitropropane as well as thermoresponsiveness in aqueous solutions are studied and compared with that of free side chains, i.e., linear PiPrOx with a hydrophobic terminal group. In nitropropane, the graft-copolymer adopts conformation of a 13-arm star with a core of a collapsed main chain and a PiPrOx corona. Similarly, a linear PiPrOx chain protects its bulky terminal group by wrapping around it in a selective solvent. In aqueous solutions at low temperatures, graft copolymers form aggregates due to interaction of hydrophobic backbones, which contrasts to molecular solutions of the model linear PiPrOx. The lower critical solution temperature (LCST) for the graft copolymer is around 20 °C. The phase separation temperatures of the copolymer solution were lower than that of the linear chain counterpart, decreasing with concentration for both polymers.

scholarly journals A thermoresponsive poly(ionic liquid) membrane enables concentration of proteins from aqueous media

2016 ◽  
Vol 52 (47) ◽  
pp. 7497-7500 ◽  
Author(s):  
Yuki Kohno ◽  
Douglas L. Gin ◽  
Richard D. Noble ◽  
Hiroyuki Ohno
Keyword(s):  
Ionic Liquid ◽  
Lower Critical Solution Temperature ◽  
Liquid Membrane ◽  
Aqueous Media ◽  
Water Soluble ◽  
Phase Behaviour ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
New Type ◽  
Poly Ionic Liquid

A new type of poly(ionic liquid) membrane, which shows switchable hydrated states via lower critical solution temperature-type phase behaviour, enables concentration of some water-soluble proteins from aqueous media.

Reversible down-regulation and up-regulation of catalytic activity of poly(N-isopropylacrylamide)-anchored gold nanoparticles

2022 ◽  
Author(s):  
Yufen Han ◽  
Jiaqian Li ◽  
Xiaojin Zhang ◽  
Fan Xia ◽  
Yu Dai
Keyword(s):  
Gold Nanoparticles ◽  
Catalytic Activity ◽  
Active Sites ◽  
Reaction Rate ◽  
High Selectivity ◽  
Light Irradiation ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Ultraviolet Light Irradiation ◽  
Surface Active

Abstract Regulating catalytic activity plays an important role in further optimizing and developing multifunctional catalysts with high selectivity and high activity. Reversible dual regulation of catalytic activity has always been a challenging task. Here, we prepared poly(N-isopropylacrylamide)-anchored gold nanoparticles (AuNP@CDs-Azo-PNIPAM) through host-guest interaction of cyclodextrin capped gold nanoparticles (AuNP@CDs) and azobenzene-terminated poly(N-isopropylacrylamide) (Azo-PNIPAM). Azo-PNIPAM as thermal and light responsive ligand allows reversible dual regulation of catalytic activity. When the temperature is higher than the lowest critical solution temperature (LCST), the PNIPAM chain shrinks rapidly, increasing the steric hindrance around AuNPs and reducing the catalytic activity. Under ultraviolet light irradiation, cis-azobenzene disassembles from cyclodextrin and the number of surface active sites of AuNPs increases, which improves the catalytic activity. The reaction rate of UV irradiation is almost 1.3 times that of visible light irradiation. This work provides a simple and effective strategy for the construction of reversible catalysts.

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