scholarly journals Synthesis and Self-Assembly of Multistimulus-Responsive Azobenzene-Containing Diblock Copolymer through RAFT Polymerization

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2028
Author(s):  
Po-Chih Yang ◽  
Yueh-Han Chien ◽  
Shih-Hsuan Tseng ◽  
Chia-Chung Lin ◽  
Kai-Yu Huang
Keyword(s):  
Uv Irradiation ◽  
Diblock Copolymer ◽  
Self Assembly ◽  
Raft Polymerization ◽  
Solution Temperature ◽  
Micellar Aggregates ◽  
Before And After ◽  
Assembly Behavior ◽  
Copolymer Poly ◽  
Polymer Aqueous Solution

This paper gathered studies on multistimulus-responsive sensing and self-assembly behavior of a novel amphiphilic diblock copolymer through a two-step reverse addition-fragmentation transfer (RAFT) polymerization technique. N-Isopropylacrylamide (NIPAM) macromolecular chain transfer agent and diblock copolymer (poly(NIPAM-b-Azo)) were discovered to have moderate thermal decomposition temperatures of 351.8 and 370.8 °C, respectively, indicating that their thermal stability was enhanced because of the azobenzene segments incorporated into the block copolymer. The diblock copolymer was determined to exhibit a lower critical solution temperature of 34.4 °C. Poly(NIPAM-b-Azo) demonstrated a higher photoisomerization rate constant (kt = 0.1295 s−1) than the Azo monomer did (kt = 0.088 s−1). When ultraviolet (UV) irradiation was applied, the intensity of fluorescence gradually increased, suggesting that UV irradiation enhanced the fluorescence of self-assembled cis-isomers of azobenzene. Morphological aggregates before and after UV irradiation are shown in scanning electron microscopy (SEM) and dynamic light scattering (DLS) analyses of the diblock copolymer. We employed photoluminescence titrations to reveal that the diblock copolymer was highly sensitive toward Ru3+ and Ba2+, as was indicated by the crown ether acting as a recognition moiety between azobenzene units. Micellar aggregates were formed in the polymer aqueous solution through dissolution; their mean diameters were approximately 205.8 and 364.6 nm at temperatures of 25.0 and 40.0 °C, respectively. Our findings contribute to research on photoresponsive and chemosensory polymer material developments.

scholarly journals Effects of Chemical Modifications on the Thermoresponsive Behavior of a PDMAEA-b-PNIPAM-b-POEGA Triblock Terpolymer

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1382 ◽  
Author(s):  
Despoina Giaouzi ◽  
Stergios Pispas
Keyword(s):  
Self Assembly ◽  
Raft Polymerization ◽  
Aqueous Media ◽  
Size Exclusion ◽  
Solution Temperature ◽  
The Novel ◽  
Chemical Modifications ◽  
Solution Ph ◽  
Assembly Behavior ◽  
Triblock Terpolymers

In this work, the synthesis, selective chemical modifications, and self-assembly behavior in aqueous media of a novel poly(2-(dimethylamino)ethyl acrylate)20-b-poly(N-isopropylacrylamide)11-b-poly(oligo ethylene glycol methyl ether acrylate)18 (PDMAEA20-b-PNIPAM11-b-POEGA18) dual-responsive (pH and temperature) and triply hydrophilic amino-based triblock terpolymer are reported. The amine functional triblock terpolymer was synthesized by sequential reversible addition fragmentation chain transfer polymerization (RAFT) polymerization and molecularly characterized by size exclusion chromatography (SEC) and 1H-NMR spectroscopy that evidenced the success of the three-step polymerization scheme. The tertiary amine pendant groups of the PDMAEA block were chemically modified in order to produce the Q1PDMAEA20-b-PNIPAM11-b-POEGA18 as well as the Q6PDMAEA20-b-PNIPAM11-b-POEGA18 quaternized triblock terpolymers (Q1 and Q6 prefixes show the number of carbon atoms (C1 and C6) attached on the PDMAEA groups) using methyl iodide (CH3I) and 1-iodohexane (C6H13I) as the quaternizing agents and the SPDMAEA20-b-PNIPAM11-b-POEGA18 sulfobetainized triblock terpolymer using 1,3 propanesultone (C3H6O3S) as the sulfobetainization agent. The self-assembly properties of the triblock terpolymers in aqueous solutions upon varying temperature and solution pH were studied by light scattering and fluorescence spectroscopy experiments. The novel triblock terpolymers self-assemble into nanosized aggregates upon solution temperature rise above the nominal lower critical solution temperature (LCST) of the temperature-responsive PNIPAM block. The remarkable stimuli-responsive self-assembly behavior of the novel triblock terpolymers in aqueous media make them interesting candidates for biomedical applications in the fields of drug and gene delivery.

Synthesis of poly(methyl methacrylate)-b-poly(acrylic acid) by DPE method

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Dong Chen ◽  
Ruixue Liu ◽  
Zhifeng Fu ◽  
Yan Shi
Keyword(s):  
Molecular Weight ◽  
Acrylic Acid ◽  
Methyl Methacrylate ◽  
Diblock Copolymer ◽  
Self Assembly ◽  
Gel Permeation Chromatography ◽  
Amphiphilic Diblock Copolymer ◽  
Poly Methyl Methacrylate ◽  
Copolymer Poly ◽  
Poly Acrylic Acid

AbstractAmphiphilic diblock copolymer poly(methyl methacrylate)-b-poly(acrylic acid) (PMMA-b-PAA) was prepared by 1,1-diphenylethene (DPE) method. Firstly, free radical polymerization of methyl methacrylate was carried out with AIBN as initiator in the presence of DPE, giving a DPE-containing PMMA precursor with controlled molecular weight. tert-Butyl acrylate (tBA) was then polymerized in the presence of the PMMA precursor, and PMMA-b-PtBA diblock copolymer with controlled molecular weight was prepared. Finally, amphiphilic diblock copolymer PMMA-b-PAA was obtained by hydrolysis of PMMA-b-PtBA. The formation of PMMA-b-PAA was confirmed by 1H NMR spectrum and gel permeation chromatography. Transmission electron microscopy and dynamic light scattering were used to detect the self-assembly behavior of the amphiphilic diblock polymers in methanol.

scholarly journals Synthesis and self-assembly of a novel amphiphilic diblock copolymer consisting of isotactic polystyrene and 1,4-trans-polybutadiene-graft-poly(ethylene oxide)

RSC Advances ◽  
2018 ◽  
Vol 8 (23) ◽  
pp. 12752-12759
Author(s):  
HuaQing Liang ◽  
QiHua Zhou ◽  
YongJiang Long ◽  
WanChu Wei ◽  
Shuo Feng ◽  
...  
Keyword(s):  
Ethylene Oxide ◽  
Diblock Copolymer ◽  
Self Assembly ◽  
Amphiphilic Diblock Copolymer ◽  
Isotactic Polystyrene ◽  
Poly Ethylene Oxide ◽  
Assembly Behavior ◽  
Poly Ethylene

Herein, a novel amphiphilic diblock copolymer consisting of isotactic polystyrene and 1,4-trans-polybutadiene-graft-poly(ethylene oxide) was synthesized and its self-assembly behavior was investigated.

Self-assembly behavior of pH- and thermo-responsive hydrophilic ABCBA-type pentablock copolymers synthesized by consecutive RAFT polymerization

RSC Advances ◽  
2013 ◽  
Vol 3 (35) ◽  
pp. 15085 ◽  
Author(s):  
Jiucun Chen ◽  
Mingzhu Liu ◽  
Chunmei Gao ◽  
Shaoyu Lü ◽  
Xinyu Zhang ◽  
...  
Keyword(s):  
Self Assembly ◽  
Raft Polymerization ◽  
Pentablock Copolymers ◽  
Assembly Behavior

scholarly journals Self-Assembly Behavior of Amphiphilic Diblock Copolymer PS-b-P4VP in CO2-Expanded Liquids

2018 ◽  
Vol 34 (8) ◽  
pp. 945-951
Author(s):  
Xiaomeng CHENG ◽  
◽  
Dongxia JIAO ◽  
Zhihao LIANG ◽  
Jinjin WEI ◽  
...  
Keyword(s):  
Diblock Copolymer ◽  
Self Assembly ◽  
Amphiphilic Diblock Copolymer ◽  
Ps I ◽  
Assembly Behavior
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