Macroscopic and microscopic shape memory effects of block copolymers prepared via ATRP

Wang, Qihua; Tao, Liming; Yang, Zenghui; Raj, Wojciech; Zhang, Yaoming; Wang, Tingmei; Pietrasik, Joanna

doi:10.1002/pola.29435

Cited by 4 publications

(2 citation statements)

References 31 publications

(31 reference statements)

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“…However, this event was observed at −30.5 • C for PNVCL-b-PCL (2) due to the increase of the PCL block length. A T g around 105.0 • C was observed for PNVCL-b-PCL (1); that can be attributed to the T g of the PNVCL block, which was shifted toward a lower temperature due to the plasticizing effect of the PCL block [50]. However, this event (i.e., the T g of the PNVCL segment) was not observed for PNVCL-b-PCL (2) due to the PCL being the dominant phase and/or due to the plasticizing effect of the PCL block being more pronounced for this copolymer that contains a longer PCL segment, or finally due to the analysis conditions.…”

Section: ε-Cl Ring-opening Polymerization Initiated By Pnvcl-oh Homopmentioning

confidence: 95%

Synthesis and Self-Assembly of Poly(N-Vinylcaprolactam)-b-Poly(ε-Caprolactone) Block Copolymers via the Combination of RAFT/MADIX and Ring-Opening Polymerizations

et al. 2020

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Well-defined amphiphilic, biocompatible and partially biodegradable, thermo-responsive poly(N-vinylcaprolactam)-b-poly(ε-caprolactone) (PNVCL-b-PCL) block copolymers were synthesized by combining reversible addition-fragmentation chain transfer (RAFT) and ring-opening polymerizations (ROP). Poly(N-vinylcaprolactam) containing xanthate and hydroxyl end groups (X–PNVCL–OH) was first synthesized by RAFT/macromolecular design by the interchange of xanthates (RAFT/MADIX) polymerization of NVCL mediated by a chain transfer agent containing a hydroxyl function. The xanthate-end group was then removed from PNVCL by a radical-induced process. Finally, the hydroxyl end-capped PNVCL homopolymer was used as a macroinitiator in the ROP of ε-caprolactone (ε-CL) to obtain PNVCL-b-PCL block copolymers. These (co)polymers were characterized by Size Exclusion Chromatography (SEC), Fourier-Transform Infrared spectroscopy (FTIR), Proton Nuclear Magnetic Resonance spectroscopy (1H NMR), UV–vis and Differential Scanning Calorimetry (DSC) measurements. The critical micelle concentration (CMC) of the block copolymers in aqueous solution measured by the fluorescence probe technique decreased with increasing the length of the hydrophobic block. However, dynamic light scattering (DLS) demonstrated that the size of the micelles increased with increasing the proportion of hydrophobic segments. The morphology observed by cryo-TEM demonstrated that the micelles have a pointed-oval-shape. UV–vis and DLS analyses showed that these block copolymers have a temperature-responsive behavior with a lower critical solution temperature (LCST) that could be tuned by varying the block copolymer composition.

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Section: ε-Cl Ring-opening Polymerization Initiated By Pnvcl-oh Homopmentioning

confidence: 95%

Synthesis and Self-Assembly of Poly(N-Vinylcaprolactam)-b-Poly(ε-Caprolactone) Block Copolymers via the Combination of RAFT/MADIX and Ring-Opening Polymerizations

et al. 2020

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“…Shape memory polymers (SMPs), as smart materials, , can change from their original shape to a temporary one and recover to their original shape in response to certain external stimuli such as temperature, − light, − electricity, , magnetism, and solvents, among others. , Compared with the conventional one-way (or irreversible) shape memory effect (1W-SME), which typically requires programming for each shape memory cycle, ,− the two-way shape memory effect (2W-SME) can realize reversible shape shifting between two distinct shapes without repeated programming. − According to whether external stress is required in the two-way shape memory cycles, the 2W-SME can be divided into quasi-2W-SME under constant external stress and reversible 2W-SME under the stress-free condition . Notably, the reversible 2W-SME is favored and more practical because it requires no external stress for reversible shape changes …”

Section: Introductionmentioning

confidence: 99%

Arbitrarily Reconfigurable and Thermadapt Reversible Two-Way Shape Memory Poly(thiourethane) Accomplished by Multiple Dynamic Covalent Bonds

Zhou

Yue

Huang

et al. 2021

ACS Appl. Mater. Interfaces

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The fabrication of a single polymer network that exhibits a good reversible two-way shape memory effect (2W-SME), can be formed into arbitrarily complex three-dimensional (3D) shapes, and is recyclable remains a challenge. Herein, we design and fabricate poly(thiourethane) (PTU) networks with an excellent thermadapt reversible 2W-SME, arbitrary reconfigurability, and good recyclability via the synergistic effects of multiple dynamic covalent bonds (i.e., ester, urethane, and thiourethane bonds). The PTU samples with good mechanical performance simultaneously demonstrate a maximum tensile stress of 29.7 ± 1.1 MPa and a high strain of 474.8 ± 7.5%. In addition, the fraction of reversible strain of the PTU with 20 wt % hard segment reaches 22.4% during the reversible 2W-SME, where the fraction of reversible strain is enhanced by self-nucleated crystallization of the PTU. A sample with arbitrarily complex permanent 3D shapes can be realized via the solid-state plasticity, and that sample also exhibits excellent reversible 2W-SME. A smart light-responsive actuator with a double control switch is fabricated using a reversible two-way shape memory PTU/MXene film. In addition, the PTU networks are de-cross-linked by alcohol solvolysis, enabling the recovery of monomers and the realization of recyclability. Therefore, the present study involving the design and fabrication of a PTU network for potential applications in intelligent actuators and multifunctional shape-shifting devices provides a new strategy for the development of thermadapt reversible two-way shape memory polymers.

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Well-defined amphiphilic poly(ε-caprolactone)-b-poly(N-isopropylacrylamide) and thermosensitive micelles formulation

de Moraes,

de Carvalho,

Teixeira

et al. 2023

Iran Polym J

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Macroscopic and microscopic shape memory effects of block copolymers prepared via ATRP

Cited by 4 publications

References 31 publications

Synthesis and Self-Assembly of Poly(N-Vinylcaprolactam)-b-Poly(ε-Caprolactone) Block Copolymers via the Combination of RAFT/MADIX and Ring-Opening Polymerizations

Synthesis and Self-Assembly of Poly(N-Vinylcaprolactam)-b-Poly(ε-Caprolactone) Block Copolymers via the Combination of RAFT/MADIX and Ring-Opening Polymerizations

Arbitrarily Reconfigurable and Thermadapt Reversible Two-Way Shape Memory Poly(thiourethane) Accomplished by Multiple Dynamic Covalent Bonds

Well-defined amphiphilic poly(ε-caprolactone)-b-poly(N-isopropylacrylamide) and thermosensitive micelles formulation

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