scholarly journals Synthesis and Characterization of Temperature-Responsive N-Cyanomethylacrylamide-Containing Diblock Copolymer Assemblies in Water

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4424
Author(s):  
Nicolas Audureau ◽  
Fanny Coumes ◽  
Clémence Veith ◽  
Clément Guibert ◽  
Jean-Michel Guigner ◽  
...  
Keyword(s):  
Diblock Copolymer ◽  
Self Assembly ◽  
Diblock Copolymers ◽  
Colloidal Stability ◽  
Aqueous Dispersion ◽  
Degree Of Polymerization ◽  
Solution Temperature ◽  
Thermoresponsive Polymers ◽  
Aqueous Synthesis ◽  
Reversible Addition

We have previously demonstrated that poly(N-cyanomethylacrylamide) (PCMAm) exhibits a typical upper-critical solution temperature (UCST)-type transition, as long as the molar mass of the polymer is limited, which was made possible through the use of reversible addition-fragmentation chain transfer (RAFT) radical polymerization. In this research article, we use for the first time N-cyanomethylacrylamide (CMAm) in a typical aqueous dispersion polymerization conducted in the presence of poly(N,N-dimethylacrylamide) (PDMAm) macroRAFT agents. After assessing that well-defined PDMAm-b-PCMAm diblock copolymers were formed through this aqueous synthesis pathway, we characterized in depth the colloidal stability, morphology and temperature-responsiveness of the dispersions, notably using cryo-transmission electron microscopy (cryo-TEM), dynamic light scattering (DLS), small angle X-ray scattering (SAXS) and turbidimetry. The combined analyses revealed that stable nanometric spheres, worms and vesicles could be prepared when the PDMAm block was sufficiently long. Concerning the thermoresponsiveness, only diblocks with a PCMAm block of a low degree of polymerization (DPn,PCMAm < 100) exhibited a UCST-type dissolution upon heating at low concentration. In contrast, for higher DPn,PCMAm, the diblock copolymer nano-objects did not disassemble. At sufficiently high temperatures, they rather exhibited a temperature-induced secondary aggregation of primary particles. In summary, we demonstrated that various morphologies of nano-objects could be obtained via a typical polymerization-induced self-assembly (PISA) process using PCMAm as the hydrophobic block. We believe that the development of this aqueous synthesis pathway of novel PCMAm-based thermoresponsive polymers will pave the way towards various applications, notably as thermoresponsive coatings and in the biomedical field.

Thermo-responsive metallo-supramolecular gels based on terpyridine end-functionalized amphiphilic diblock copolymers

2013 ◽  
Vol 1499 ◽  
Author(s):  
Jérémy Brassinne ◽  
Charles-André Fustin ◽  
Jean-François Gohy
Keyword(s):  
Mechanical Properties ◽  
Diblock Copolymer ◽  
Self Assembly ◽  
Micellar Solution ◽  
Diblock Copolymers ◽  
Solution Temperature ◽  
Selective Solvent ◽  
Critical Solution Temperature ◽  
Terpyridine Ligands ◽  
Amphiphilic Diblock Copolymers

ABSTRACTA thermo-responsive hydrogel was prepared on the basis of terpyridine endfunctionalized polystyrene-block-poly(N-isopropylacrylamide) diblock copolymer. As a first level of assembly, the copolymer was dissolved in a selective solvent to yield micelles bearing terpyridine ligands at the extremity of the coronal chains. The second level of self-assembly was triggered upon addition of metal ions to the micellar solution. Mechanical properties of the accordingly obtained micellar gel were finally characterized by rotational rheometry, below and above the lower critical solution temperature.

scholarly journals In situ SAXS studies of a prototypical RAFT aqueous dispersion polymerization formulation: monitoring the evolution in copolymer morphology during polymerization-induced self-assembly

2020 ◽  
Vol 11 (42) ◽  
pp. 11443-11454 ◽  
Author(s):  
Adam Czajka ◽  
Steven P. Armes
Keyword(s):  
Diblock Copolymer ◽  
Small Angle ◽  
Self Assembly ◽  
Dispersion Polymerization ◽  
Chain Transfer ◽  
Aqueous Dispersion ◽  
X Ray ◽  
X Ray Scattering ◽  
Reversible Addition

In situ small-angle X-ray scattering is used to monitor the formation of diblock copolymer spheres, worms and vesicles during reversible addition-fragmentation chain transfer (RAFT) aqueous dispersion polymerization of 2-hydroxypropyl methacrylate.

Self-assembly of hydrophobic-amphiphilic diblock copolymers in solution

2021 ◽  
Author(s):  
Sophia Pavlenko ◽  
Daniil E Larin ◽  
Elena Nikolaevna Govorun
Keyword(s):  
Diblock Copolymer ◽  
Self Assembly ◽  
Diblock Copolymers ◽  
Mean Field ◽  
Chain Structure ◽  
Spherical Particles ◽  
Condensed State ◽  
Thermoresponsive Polymers ◽  
Polar Groups ◽  
Amphiphilic Diblock Copolymers

Abstract Thermoresponsive polymers are usually characterized by a locally amphiphilic chain structure and their self-assembly in solution is controlled, in particular, by the surface activity of the monomer units or side chains. We theoretically study the condensed state of a single diblock copolymer molecule consisting of a hydrophobic block and amphiphilic block with hydrophobic groups in the backbone and pendant polar groups. The equilibrium parameters of the polymer globules of different shapes are determined using the mean-field approach to determine the most favorable structure. Morphological diagrams of condensed macromolecules are presented depending on the chain length, amphiphilic block fraction, interaction parameters, and pendant volume and length. The diagrams are compared with those of a copolymer molecule with the same fraction of amphiphilic monomer units which are regularly distributed along the chain. The diblock copolymer molecule is found to form a single spherical or flattened particle, with the core from the hydrophobic block, or a granular micelle consisting of spherical or nearly spherical particles, in agreement with the experimental data in the literature. The optimal chain parameters for self-assembly into a stable single core-shell particle are predicted.

scholarly journals RAFT aqueous dispersion polymerization of 4-hydroxybutyl acrylate: effect of end-group ionization on the formation and colloidal stability of sterically-stabilized diblock copolymer nanoparticles

2022 ◽  
Author(s):  
Deborah L. Beattie ◽  
Oliver J. Deane ◽  
Oleksandr O. Mykhaylyk ◽  
Steven P. Armes
Keyword(s):  
Diblock Copolymer ◽  
Self Assembly ◽  
Dispersion Polymerization ◽  
Colloidal Stability ◽  
Aqueous Dispersion ◽  
Aqueous Polymerization ◽  
Raft Agent ◽  
End Group

Poly(2-hydroxyethyl acrylate)-poly(4-hydroxybutyl acrylate) nano-objects are prepared by aqueous polymerization-induced self-assembly (PISA) using an ionic RAFT agent.

Self-assembly of linear diblock copolymers in selective solvents: from single micelles to particles with tri-continuous inner structures

Soft Matter ◽  
2020 ◽  
Vol 16 (26) ◽  
pp. 6056-6062 ◽  
Author(s):  
Xianggui Ye ◽  
Bamin Khomami
Keyword(s):  
Diblock Copolymer ◽  
Self Assembly ◽  
Large Scale ◽  
Diblock Copolymers ◽  
Dissipative Particle Dynamics ◽  
Particle Dynamics ◽  
The Self ◽  
Selective Solvent ◽  
Selective Solvents

Large-scale dissipative particle dynamics (DPD) simulations have been performed to investigate the self-assembly of over 20 000 linear diblock copolymer chains in a selective solvent.

scholarly journals Uniform electroactive fibre-like micelle nanowires for organic electronics

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Xiaoyu Li ◽  
Piotr J. Wolanin ◽  
Liam R. MacFarlane ◽  
Robert L. Harniman ◽  
Jieshu Qian ◽  
...  
Keyword(s):  
Block Copolymers ◽  
Charge Carrier ◽  
Self Assembly ◽  
Diblock Copolymers ◽  
Field Effect Transistors ◽  
Fibre Length ◽  
Charge Carrier Mobility ◽  
Degree Of Polymerization ◽  
Selective Solvents ◽  
The Individual

Abstract Micelles formed by the self-assembly of block copolymers in selective solvents have attracted widespread attention and have uses in a wide variety of fields, whereas applications based on their electronic properties are virtually unexplored. Herein we describe studies of solution-processable, low-dispersity, electroactive fibre-like micelles of controlled length from π-conjugated diblock copolymers containing a crystalline regioregular poly(3-hexylthiophene) core and a solubilizing, amorphous regiosymmetric poly(3-hexylthiophene) or polystyrene corona. Tunnelling atomic force microscopy measurements demonstrate that the individual fibres exhibit appreciable conductivity. The fibres were subsequently incorporated as the active layer in field-effect transistors. The resulting charge carrier mobility strongly depends on both the degree of polymerization of the core-forming block and the fibre length, and is independent of corona composition. The use of uniform, colloidally stable electroactive fibre-like micelles based on common π-conjugated block copolymers highlights their significant potential to provide fundamental insight into charge carrier processes in devices, and to enable future electronic applications.

scholarly journals Synthesis of Poly(3-vinylpyridine)-Block-Polystyrene Diblock Copolymers via Surfactant-Free RAFT Emulsion Polymerization

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3145 ◽  
Author(s):  
Katharina Nieswandt ◽  
Prokopios Georgopanos ◽  
Clarissa Abetz ◽  
Volkan Filiz ◽  
Volker Abetz
Keyword(s):  
Emulsion Polymerization ◽  
Self Assembly ◽  
Diblock Copolymers ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Free Water ◽  
Monomer Conversion ◽  
Molecular Weights ◽  
Reversible Addition

In this work, we present a novel synthetic route to diblock copolymers based on styrene and 3-vinylpyridine monomers. Surfactant-free water-based reversible addition–fragmentation chain transfer (RAFT) emulsion polymerization of styrene in the presence of the macroRAFT agent poly(3-vinylpyridine) (P3VP) is used to synthesize diblock copolymers with molecular weights of around 60 kDa. The proposed mechanism for the poly(3-vinylpyridine)-block-poly(styrene) (P3VP-b-PS) synthesis is the polymerization-induced self-assembly (PISA) which involves the in situ formation of well-defined micellar nanoscale objects consisting of a PS core and a stabilizing P3VP macroRAFT agent corona. The presented approach shows a well-controlled RAFT polymerization, allowing for the synthesis of diblock copolymers with high monomer conversion. The obtained diblock copolymers display microphase-separated structures according to their composition.

scholarly journals Upper Critical Solution Temperature (UCST) Behavior of Polystyrene-Based Polyampholytes in Aqueous Solution

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 265 ◽  
Author(s):  
Komol Kanta Sharker ◽  
Yuki Ohara ◽  
Yusuke Shigeta ◽  
Shinji Ozoe ◽  
Shin-ichi Yusa
Keyword(s):  
Pure Water ◽  
Polymer Concentration ◽  
Degree Of Polymerization ◽  
Solution Temperature ◽  
Sulfonate Group ◽  
Trimethylammonium Chloride ◽  
Critical Solution Temperature ◽  
Reversible Addition ◽  
Upper Critical Solution Temperature ◽  
Quaternary Ammonium Group

Strong polyampholytes comprising cationic vinylbenzyl trimethylammonium chloride (VBTAC) bearing a pendant quaternary ammonium group and anionic sodium p-styrenesulfonate (NaSS) bearing a pendant sulfonate group were prepared via reversible addition-fragmentation chain-transfer polymerization. The resultant polymers are labelled P(VBTAC/NaSS)n, where n indicates the degree of polymerization (n = 20 or 97). The percentage VBTAC content in P(VBTAC/NaSS)n is always about 50 mol%, as revealed by 1H NMR measurements, meaning that P(VBTAC/NaSS)n is a close to stoichiometrically charge-neutralized polymer. Although P(VBTAC/NaSS)n cannot dissolve in pure water at room temperature, the addition of NaCl or heating solubilizes the polymers. Furthermore, P(VBTAC/NaSS)n exhibits upper critical solution temperature (UCST) behavior in aqueous NaCl solutions. The UCST is shifted to higher temperatures by increasing the polymer concentration and molecular weight, and by decreasing the NaCl concentration. The UCST behavior was measured ranging the polymer concentrations from 0.5 to 5.0 g/L.

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.

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