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 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 Hydrophobic Modifications on the Solution Self-Assembly of P(DMAEMA-co-QDMAEMA)-b-POEGMA Random Diblock Copolymers

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 338
Author(s):  
Martha Kafetzi ◽  
Stergios Pispas
Keyword(s):  
Aqueous Solution ◽  
Self Assembly ◽  
Diblock Copolymers ◽  
Raft Polymerization ◽  
Temperature Response ◽  
High Mass ◽  
Alkyl Chains ◽  
Release Studies ◽  
Solution Preparation ◽  
Assembly Behavior

In this work, the synthesis and the aqueous solution self-assembly behavior of novel partially hydrophobically modified poly(2-(dimethylamino) ethyl methacrylate)-b-poly(oligo(ethylelene glycol) methyl ether methacrylatetabel) pH and temperature responsive random diblock copolymers (P(DMAEMA-co-Q6/12DMAEMA)-b-POEGMA), are reported. The chemical modifications were accomplished via quaternization with 1-iodohexane (Q6) and 1-iodododecane (Q12) and confirmed by 1H-NMR spectroscopy. The successful synthesis of PDMAEMA-b-POEGMA precursor block copolymers was conducted by RAFT polymerization. The partial chemical modification of the diblocks resulted in the permanent attachment of long alkyl chains on the amine groups of the PDMAEMA block and the presence of tertiary and quaternary amines randomly distributed within the PDMAEMA block. Light scattering techniques confirmed that the increased hydrophobic character results in the formation of nanoaggregates of high mass and tunable pH and temperature response. The characteristics of the aggregates are also affected by the aqueous solution preparation protocol, the nature of the quaternizing agent and the quaternization degree. The incorporation of long alkyl chains allowed the encapsulation of indomethacin within the amphiphilic diblock copolymer aggregates. Nanostructures of increased size were detected due to the encapsulation of indomethacin into the interior of the hydrophobic domains. Drug release studies demonstrated that almost 50% of the encapsulated drug can be released on demand by aid of ultrasonication.

Double thermoresponsive pentablock copolymers: synthesis by one-pot RAFT polymerization and self-assembly in aqueous solutions

2017 ◽  
Vol 8 (46) ◽  
pp. 7217-7228 ◽  
Author(s):  
Povilas Radzevicius ◽  
Medeina Steponaviciute ◽  
Tatjana Krivorotova ◽  
Ricardas Makuska
Keyword(s):  
Aqueous Solutions ◽  
Self Assembly ◽  
Raft Polymerization ◽  
Block Sequence ◽  
One Pot ◽  
Sequence Dependent ◽  
Pentablock Copolymers

Pentablock copolymers synthesized by one-pot successive RAFT polymerization are double thermoresponsive and exhibit block sequence dependent aggregation in aqueous solutions.

Effect of Selective Solvents on Self-Assembly of Cationic Amphiphilic Triblock Copolymers Q-PVBC-b-PS-B-Q-PVBC

2013 ◽  
Vol 787 ◽  
pp. 245-249
Author(s):  
Bing Bing Yang ◽  
Yan Shi ◽  
Zhi Feng Fu
Keyword(s):  
Self Assembly ◽  
Triblock Copolymer ◽  
Raft Polymerization ◽  
The Self ◽  
Amphiphilic Block Copolymers ◽  
Selective Solvent ◽  
Selective Solvents ◽  
Amphiphilic Triblock Copolymer ◽  
Ps I ◽  
Assembly Behavior

Self-assembly behavior of an cationic amphiphilic triblock copolymer Q-PVBC -b-PS-b-Q-PVBC in DMF/water and DMF/methanol were studied. Well defined triblock copolymer PVBC-b-PS-b-PVBC was synthesized by RAFT polymerization and the cationic amphiphilic block copolymers Q-PVBC-b-PS-b-Q-PVBC was obtained by the quaternization of hydrophobic precursors with triethylamine. It is concluded that that selective solvents had a great effect on the self-assemble morphologies of the polymer. Comparing to the micelles treating water as the selective solvent, the aggregates using methanol were irregular spheres and had larger diameter.

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.

Self-Assembly of Single Chain Janus Nanoparticles from Azobenzene-Containing Block Copolymers and Reversible Photoinduced Morphology Transition

2021 ◽  
Author(s):  
Wei Wen ◽  
Aihua Chen
Keyword(s):  
Block Copolymers ◽  
Experimental Research ◽  
Self Assembly ◽  
The Self ◽  
Single Chain ◽  
Morphology Transition ◽  
Janus Nanoparticles ◽  
Assembly Behavior

Self-assembly of amphiphilic single chain Janus nanoparticles (SCJNPs) is a novel and promising approach to fabricate assemblies with diversified morphologies. However, the experimental research of the self-assembly behavior of SCJNPs...

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