80 research outputs found
Self-healing polyurethane elastomers based on charge-transfer interactions for biomedical applications
One promising application of self-healing polymeric materials is biomedical use. Although charge-transfer (CT) interactions have been employed to construct self-healing polymers as well as other reversible bonds and interactions, their potential for biomedical applications has never been investigated. In this study, we fabricated self-healable and cell-compatible polyurethane elastomers cross-linked by CT complexes between electron-rich pyrene (Py) and electron-deficient naphthalene diimide (NDI) by simply blending two linear polymers with Py or NDI as a repeating unit. The elastomers with different blend ratios self-healed damage over 1 day in mild conditions, including in air and water at 30–100 °C. The mechanical properties of damaged elastomers were almost restored after healing in air at 100 °C, and even in air at 30 °C and in water at 70 °C, healing was also possible to a certain extent. The good cell compatibility of the polyurethane elastomers was demonstrated by culturing two kinds of cells on the thin film substrates.This work was supported by JSPS KAKENHI (Grant No. 16H07292 and 19K15623, KI), MEXT LEADER (Grant No. A6501, KI), and the Izumi Science and Technology Foundation (Grant No. H29-J-113, KI). A research grant from the Mitsubishi Materials–Faculty of Science and Engineering, Waseda University (2016, 2018) and a Grant for Young Scientists Encouragement from the Waseda Research Institute for Science and Engineering–JXTG Energy (2017) are also acknowledged for financial support
Synthesis, Optical and Electrochemical Properties of Benzofuro[2,3-c]carbazoloquinol Fluorescent Dyes
Benzofuro[2,3-c]carbazoloquinol derivatives, a new type of fluorescent dyes, were derived from the corresponding quinone, and their optical and electrochemical properties were investigated by photoabsorption and fluorescence spectroscopy, cyclic voltammetry (CV) and density functional theory (DFT) calculation. The quinol derivatives in 1,4-dioxane showed the photoabsorption band at around 435 nm (molar extinction coefficient (εmax) = ca. 6000–8000 M−1 cm−1) and the fluorescence band at around 520 nm (fluorescence quantum yield (Φfl) = 0.24–0.28). The CV demonstrated that the quinol derivatives exhibit an irreversible oxidation wave at around −0.28 V versus Fc/Fc+. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energy levels of the quinol derivatives which were calculated using DFT at the B3LYP/6-31G(d,p) level are in good agreement with the experimental results
Self-healing polyurethane elastomers based on charge-transfer interactions for biomedical applications
Diarylbibenzofuranone-Based Dynamic Covalent Polymer Gels Prepared via Radical Polymerization and Subsequent Polymer Reaction
Diarylbibenzofuranone (DABBF) is a dynamic covalent bonding unit, which is in equilibrium with the corresponding radicals at room temperature, and polymers with DABBF linkages show notable properties such as self-healing. The preparation routes have been strictly limited, however, and no polymer with the linkages has been synthesized via radical polymerization because of the strong antioxidant activity of DABBF. Here we present a new method to prepare DABBF-containing polymers via radical polymerization of the precursor, arylbenzofuranone (ABF), and subsequent polymer reaction, dimerization of ABF units in the linear polymers. Polymer gels cross-linked by DABBF linkages were obtained against the relatively strong antioxidant activity of ABF and showed dynamic network reorganization at room temperature
Self-Healing of a Cross-Linked Polymer with Dynamic Covalent Linkages at Mild Temperature and Evaluation at Macroscopic and Molecular Levels
A lot
of self-healing materials using dynamic bonding systems have
been reported, while the focus is mainly on the macroscopic self-healing
behavior such as visually recognizable healing. Because the healing
originates from microscopic chemical reactions of the dynamic bonds,
evaluation of the reactions in the materials is necessary for elucidation
of the healing mechanisms and development of the healing ability.
Herein, we demonstrated self-healing of a cross-linked polymer with
diarylbibenzofuranone (DABBF)-based dynamic covalent linkages at mild
temperature and investigated the healing behavior from both macroscopic
and microscopic viewpoints. The macroscopic behavior was inspected
by mechanical tests, and the linkage reaction (equilibrium) was evaluated
by electron paramagnetic resonance measurements. These assessments
revealed that the healing is strongly dependent on temperature, which
is attributable to synergism between changes in the chain mobility
and in the equilibrium of the incorporated linkages. These findings
would be applicable to other dynamic bonding systems
Responsive Dynamic Covalent Polymers: Self-Healing Polymers through Dynamic Covalent Chemistry
Reorganizable of Polymer Structures Based on Dynamic Covalent Chemistry: Polymer Reactions by Dynamic Covalent Exchanges of Diarylbibenzofuranones
Polymer–Inorganic Composites with Dynamic Covalent Mechanochromophore
Polymer–inorganic
composites with diarylbibenzofuranone
(DABBF) moieties, dynamic covalent mechanochromophores, were prepared,
and their mechanochromic behavior was systematically investigated.
The central C–C bonds in DABBF moieties can be cleaved by mechanical
force to form the corresponding stable blue radicals, which can be
quantitatively evaluated by electron paramagnetic resonance (EPR)
spectroscopy. One controversial issue but attractive property in the
DABBF system is the equilibrium between the activated and deactivated
states. Although the deactivation process decreases the sensitivity
of some equilibrium mechanophores, the equilibrium has rarely been
considered when establishing molecular and/or material design of these
systems. Herein, a rational macromolecular design to suppress the
deactivation of activated dynamic mechanophores and improve sensitivity
by limiting their molecular motion is proposed. Polymer–inorganic
composite materials with rigid networks prepared from DABBF alkoxysilane
derivatives exhibited significant activation of the incorporated DABBF
linkages by grinding, with sensitivities more than 50 times as high
as that of DABBF monomers. The increased sensitivity is due to the
effective transmission of mechanical force to the DABBF moieties in
the network structures and suppression of the recombination of the
generated radicals by the rigid frameworks. Furthermore, when the
rigid frameworks were incorporated into elastomers as inorganic hard
domains, the DABBF mechanophores at the interface between the organic
and inorganic domains were preferentially activated by elongation
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