Electron Spin Resonance Spectroscopy

Schlick, Shulamith; Jeschke, Gunnar

doi:10.1016/b978-0-444-53349-4.00027-3

Cited by 6 publications

(6 citation statements)

References 111 publications

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“…Electron paramagnetic resonance (EPR) constitutes another alternative involving a static magnetic field. The EPR technique is an analog-based technique to NMR in which electron spins are excited instead of the spins of atomic nuclei to study materials with unpaired electrons, which is useful for metal complexes or organic radicals [ 195 ]. The photodynamic activity of polymersomes, including photosensitizers (PSs), has been studied with the EPR technique, which detects the production of reactive oxygen species (ROS) with irradiation, indicating the formation of paramagnetic species [ 196 ].…”

Section: Polymersomes As a Platform For Anticancer Therapeutic Deliverymentioning

confidence: 99%

Light-Triggered Polymersome-Based Anticancer Therapeutics Delivery

et al. 2022

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Polymersomes are biomimetic cell membrane-like model structures that are self-assembled stepwise from amphiphilic copolymers. These polymeric (nano)carriers have gained the scientific community’s attention due to their biocompatibility, versatility, and higher stability than liposomes. Their tunable properties, such as composition, size, shape, and surface functional groups, extend encapsulation possibilities to either hydrophilic or hydrophobic cargoes (or both) and their site-specific delivery. Besides, polymersomes can disassemble in response to different stimuli, including light, for controlling the “on-demand” release of cargo that may also respond to light as photosensitizers and plasmonic nanostructures. Thus, polymersomes can be spatiotemporally stimulated by light of a wide wavelength range, whose exogenous response may activate light-stimulable moieties, enhance the drug efficacy, decrease side effects, and, thus, be broadly employed in photoinduced therapy. This review describes current light-responsive polymersomes evaluated for anticancer therapy. It includes light-activable moieties’ features and polymersomes’ composition and release behavior, focusing on recent advances and applications in cancer therapy, current trends, and photosensitive polymersomes’ perspectives.

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Section: Polymersomes As a Platform For Anticancer Therapeutic Deliverymentioning

confidence: 99%

Light-Triggered Polymersome-Based Anticancer Therapeutics Delivery

et al. 2022

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“…To characterize the strengthening mechanism on the molecular scale, ESR analysis of untreated and HLEBI-treated PPS plies was carried out. This is because ESR has been widely implemented as a tool to characterize reaction mechanisms in polymer systems detecting free radicals during chain growth, or depolymerization reactions [ 56 ]. Dangling bonds are free radicals that are typically immobile [ 56 ].…”

Section: Resultsmentioning

confidence: 99%

“…This is because ESR has been widely implemented as a tool to characterize reaction mechanisms in polymer systems detecting free radicals during chain growth, or depolymerization reactions [ 56 ]. Dangling bonds are free radicals that are typically immobile [ 56 ].…”

Section: Resultsmentioning

confidence: 99%

“…On the contrary, the higher dose of 10 kGy HLEBI resulted in an AR-S peak at maximum intensity, indicating maximum AR-S dangling bond density. This indicates an increase in free radicals [ 56 ], apparently shortening PPS chains and lowering molecular weight of the PPS, acting to lower the a uc . Likewise, 15 and 20 kGy peaks were higher than untreated and 5 kGy samples.…”

Section: Resultsmentioning

confidence: 99%

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A New Strengthening Process for Carbon-Fiber-Reinforced Thermoplastic Polyphenylene Sulfide (CFRTP-PPS) Interlayered Composite by Electron Beam Irradiation to PPS Prior to Lamination Assembly and Hot Press

et al. 2023

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Impact by hailstone, volcanic rock, bird strike, or also dropping tools can cause damage to aircraft materials. For maximum safety, the goal is to increase Charpy impact strength (auc) of a carbon-fiber-reinforced thermoplastic polyphenylene sulfide polymer (CFRTP-PPS) composite for potential application to commercial aircraft parts. The layup was three cross-weave CF plies alternating between four PPS plies, [PPS-CF-PPS-CF-PPS-CF-PPS], designated [PPS]4[CF]3. To strengthen, a new process for CFRP-PPS was employed applying homogeneous low voltage electron beam irradiation (HLEBI) to both sides of PPS plies prior to lamination assembly with untreated CF, followed by hot press under 4.0 MPa at 573 K for 8 min. Experimental results showed a 5 kGy HLEBI dose was at or near optimum, increasing auc at each accumulative probability, Pf. Optical microscopy of 5 kGy sample showed a reduction in main crack width with significantly reduced CF separation and pull-out; while, scanning electron microscopy (SEM) and electron dispersive X-ray (EDS) mapping showed PPS adhering to CF. Electron spin resonance (ESR) of a 5 kGy sample indicated lengthening of PPS chains as evidenced by a reduction in dangling bond peak. It Is assumed that 5 kGy HLEBI creates strong bonds at the interface while strengthening the PPS bulk. A model is proposed to illustrate the possible strengthening mechanism.

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“…Particularly, the doping effect is often utilized to improve the electrical conductivity of the cathode interlayer, including self‐doping of the CIMs or with added dopant 52,53 . The doping effect is usually detected by the electron spin resonance (ESR) spectrum, 54 which is a technique for studying chemical species that have one or more unpaired electrons, such as organic and inorganic free radicals or inorganic complexes possessing a transition metal ion. For the study of CIMs, an ESR signal of organic free radicals stands for the electron transfer process in CIMs or between CIMs and acceptors in the active layer.…”

Section: Work Mechanism Of the Cathode Interlayersmentioning

confidence: 99%

Perylene‐diimide‐based cathode interlayer materials for high performance organic solar cells

Jia

Chen

Zhang

et al. 2022

SusMat

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Organic solar cells (OSCs), benefiting from their significant advantages, such as light weight, flexibility, low cost, and large area manufacturing adaptability, are considered promising clean energy technologies. Currently, the power conversion efficiency (PCE) of state-of-the-art OSCs has reached over 18% through materials and device engineering. Specifically, cathode engineering with cathode interlayer materials (CIMs) is an important strategy to improve the PCEs and stability of OSCs. Among various CIMs reported in the literature, perylene diimides (PDIs) are more appropriate for working as cathode interlayers in OSCs owing to their distinct advantages of suitable energy levels, high electron affinity, high electron mobility, and facile modification. In this review, the mechanism of cathode engineering is concisely summarized, and recent research progress on PDI derivatives working as CIMs in OSCs is systematically reviewed. Finally, prospects and suggestions are provided for the development of PDI-based CIMs for practical applications.

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Electron Spin Resonance Spectroscopy

Cited by 6 publications

References 111 publications

Light-Triggered Polymersome-Based Anticancer Therapeutics Delivery

Light-Triggered Polymersome-Based Anticancer Therapeutics Delivery

A New Strengthening Process for Carbon-Fiber-Reinforced Thermoplastic Polyphenylene Sulfide (CFRTP-PPS) Interlayered Composite by Electron Beam Irradiation to PPS Prior to Lamination Assembly and Hot Press

Perylene‐diimide‐based cathode interlayer materials for high performance organic solar cells

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