High‐resolution MALDI‐TOF MS study on analysis of low‐molecular‐weight products from photo‐oxidation of poly(3‐hexylthiophene)

Mizukado, Junji; Sato, Hiroaki; Chen, Liang; Suzuki, Yasuyuki; Yamane, Satoshi; Aoyama, Yasunori; Yoshida, Yūji; Suda, Hiroyuki

doi:10.1002/jms.3614

Cited by 11 publications

(8 citation statements)

References 38 publications

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“…For the irradiated P(ProDOT) films, both neutral and charge carrier absorbances showed a slight blue shift compared to the pristine film (80–100 nm, 0.15 eV for the near-IR peak and 20 nm for the neutral peak, 0.2 eV). Blue shifting absorbance peaks are characteristics of a decrease in effective conjugation length in a conjugated polymer as has been shown for irradiation studies in solution where substantial chain fragmentation was observed . The right electrode absorbance showed a similar trend in terms of the blue shift of the neutral state absorption (10–23 nm) and also showed a peak in the near-infrared at longer wavelengths (865–955 nm), likely due to a partially de-doped underlying PEDOT:PSS electrode.…”

Section: Results Sectionsupporting

confidence: 55%

“…Blue shifting absorbance peaks are characteristics of a decrease in effective conjugation length in a conjugated polymer as has been shown for irradiation studies in solution where substantial chain fragmentation was observed. 42 The right electrode absorbance showed a similar trend in terms of the blue shift of the neutral state absorption (10−23 nm) and also showed a peak in the near-infrared at longer wavelengths (865−955 nm), likely due to a partially de-doped underlying PEDOT:PSS electrode. In addition to the shifts of the absorbance peaks, the P(ProDOT) from irradiated devices was rendered insoluble in toluene as shown in Figure S9 where the pristine sample dissolved immediately, and the irradiated samples were undissolved after a 10 min soak.…”

Section: ■ Introductionmentioning

confidence: 69%

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Photostability of Ambient-Processed, Conjugated Polymer Electrochromic Devices Encapsulated by Bioderived Barrier Films

Lang

Dillon

et al. 2021

ACS Sustainable Chem. Eng.

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Polymer-based electrochromic devices (ECDs) are a promising technology for enabling low-voltage, disposable displays, yet are currently limited by photo-oxidative bleaching of the active materials. Here, renewable barrier films composed of cellulose and chitin are presented as an alternative to poly(ethylene terephthalate) (PET) for encapsulating ECDs. To assess barrier film effectiveness, lateral ECDs composed of poly(3,4-propylenedioxythiophene-(CH2OEtHx)2) (P(ProDOT)) active layers were constructed and encapsulated with a multilayer barrier consisting of chitin nanofibers and cellulose nanocrystals spray cast onto a cellulose acetate substrate (oxygen transmission rate (OTR) = 29 cm3 m–2 day–1), a commercially available PET film (OTR = 8.5 cm3 m–2 day–1), and a high-performance PET-Al2O3 multilayer barrier film (OTR < 1 cm3 m–2 day–1). The photodegradation of the P(ProDOT) active layer was determined by measuring the evolution of the colorimetric contrast (ΔE*) and switching speeds as a function of light exposure (100 mW cm–2, AM 1.5 G light). Photodegradation was found to proceed at a similar rate for all encapsulated devices (roughly 10 times more slowly than unencapsulated devices), highlighting the opportunity for replacing petroleum packaging with bioderived barrier films. Analysis of the switching kinetics, the shifts in optical absorbance, and evidence of chemical degradation indicate that both photochemical breakdown of the electrolyte and cross-linking of the P(ProDOT) active material are key drivers for loss of device performance when oxygen flux to the active material is limited. Pathways toward better understanding photodegradation are then proposed with sustainability in mind for future ECD design.

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Section: Results Sectionsupporting

confidence: 55%

Section: ■ Introductionmentioning

confidence: 69%

Photostability of Ambient-Processed, Conjugated Polymer Electrochromic Devices Encapsulated by Bioderived Barrier Films

Lang

Dillon

et al. 2021

ACS Sustainable Chem. Eng.

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“…DCTB is well-known for its efficient desorption/ionization capabilities at low laser fluences, which has been linked to its high molar absorption coefficient. 81 Its application range is somewhat limited, predominantly for analysis of polymers 82 , fullerens 83 , organometallics 84 and more recently nanoparticles and nanoclusters 85 . DCTB's mode of action in these applications is that of an aprotic, electron-transfer (ET) secondary reaction matrix, delivering primarily radical ions in positive ion mode, or, when purposely forced, cationized molecules of the investigated compounds.…”

Section: Resultsmentioning

confidence: 99%

Toward Higher Sensitivity in Quantitative MALDI Imaging Mass Spectrometry of CNS Drugs Using a Nonpolar Matrix

et al. 2018

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Tissue-specific ion suppression is an unavoidable matrix effect in MALDI mass spectrometry imaging (MSI), the negative impact of which on precision and accuracy in quantitative MALDI-MSI can be reduced to some extent by applying isotope internal standards for normalization and matrix-matched calibration routines. The detection sensitivity still suffers, however, often resulting in significant loss of signal for the investigated analytes.An MSI application considerably affected by this phenomenon is the quantitative spatial analysis of central nervous system (CNS) drugs. Most of these drugs are low molecular weight, lipophilic compounds, which exhibit inefficient desorption and ionization during MALDI using conventional polar acidic matrices (CHCA, DHB). Here, we present the application of the (2-[(2E)-3-(4-tert-butylphenyl)-2-methylprop-2-enylidene]malononitrile) matrix for high sensitivity imaging of CNS drugs in mouse brain sections. Since DCTB is usually described as electron-transfer matrix, we provide a rationale (i.e. computational calculations of gas-phase proton affinity and ionization energy) for an additional protontransfer ionization mechanism with this matrix. Furthermore, we compare the extent of signal suppression for five different CNS drugs when employing DCTB versus CHCA matrices. The results showed that the signal suppression was not only several times lower with DCTB than with CHCA, but also depended on the specific tissue investigated. Finally, we present the application of DCTB and ultra-high resolution Fourier-transform ion cyclotron resonance mass spectrometry to quantitative MALDI imaging of the anesthetic drug xylazine in mouse brain sections based on a linear matrix-matched calibration curve. DCTB afforded up to 100fold signal intensity improvement over CHCA when comparing representative single MSI pixels, and > 440-fold for the averaged mass spectrum of the adjacent tissue sections.

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“…A few reports have detected homocoupling defects using MALDI-TOF MS in CPs when using both conventional cross-coupling and DHAP techniques. ,− End group analysis and molecular weight determination of poly(3-hexythiophene) (P3HT) is an area where MALDI-TOF MS has assisted with optimizing polymerization conditions and providing evidence for proposed mechanisms. − More specifically, MALDI-TOF MS has aided with confirming a chain-growth mechanism in the Kumada catalyst-transfer polycondensation (CTP) method for the precise growth of P3HT by determining end group functionalization . With this end group control, there have been several reports regarding the incorporation of a variety of functional end groups such as phenyl, benzyl, vinyl, and allyl, which were all confirmed with MALDI spectra. , Additionally, MALDI-TOF MS has been used in determining the mechanism of photo-oxidized degradation in P3HT films through analyzing oxidized byproducts after illumination . Although P3HT is the most commonly studied conjugated polymer using MALDI-TOF MS, due to facile end group control, there have been other examples of using MALDI-TOF MS to determine end-capping efficiency in conventional metal-mediated step-growth type polymerizations. ,, …”

Section: Introductionmentioning

confidence: 99%

Curious Case of BiEDOT: MALDI-TOF Mass Spectrometry Reveals Unbalanced Monomer Incorporation with Direct (Hetero)arylation Polymerization

et al. 2020

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Homocoupling defects in conjugated polymers often go undetected but may cause significant batch-to-batch variations that ultimately give seemingly identical polymers different material properties. These defects may go easily unnoticed because conjugated polymers are commonly characterized via gelpermeation chromatography and elemental analysis, two techniques that are not able to provide information on monomer incorporation or end groups. Nuclear magnetic resonance spectroscopy has provided evidence of homocoupling defects, but is limited to polymeric repeat units with distinct chemical shifts and little spectral overlap, a luxury unavailable in polymeric dioxythiophenes. Here, matrix-assisted laser desorption/ionization timeof-flight (MALDI-TOF) mass spectrometry (MS) was used to characterize different dioxythiophene copolymer (PE 2 ) batches based on 3,4-propylenedioxythiophene (ProDOT) and 2,2′-bis-(3,4-ethylenedioxy)thiophene (biEDOT) to elucidate changes in structure within different polymer batches. It was determined through the analysis of MALDI-TOF mass spectra that excess biEDOT is incorporated into PE 2 when using standard direct (hetero)arylation polymerization (DHAP) conditions. It is hypothesized that the high nucleophilicity of biEDOT causes uncontrolled concerted metalation−deprotonation steps in the DHAP catalytic cycle at high temperatures. To improve control of the biEDOT incorporation, the reaction temperature was lowered from 140 to 80 °C, and a different polymerization procedure was used where the reaction temperature was ramped-up from room temperature. Ultimately, incorporation of excess biEDOT was advantageous to the conductivity of oxidatively doped polymer films, with values greater than 200 and 80 S/cm for the high-and low-temperature polymerizations, respectively. This work correlates small differences in polymer structure with solid-state conductivity to expose how batch-to-batch variations regarding homocouplings can produce different material properties.

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High‐resolution MALDI‐TOF MS study on analysis of low‐molecular‐weight products from photo‐oxidation of poly(3‐hexylthiophene)

Cited by 11 publications

References 38 publications

Photostability of Ambient-Processed, Conjugated Polymer Electrochromic Devices Encapsulated by Bioderived Barrier Films

Photostability of Ambient-Processed, Conjugated Polymer Electrochromic Devices Encapsulated by Bioderived Barrier Films

Toward Higher Sensitivity in Quantitative MALDI Imaging Mass Spectrometry of CNS Drugs Using a Nonpolar Matrix

Curious Case of BiEDOT: MALDI-TOF Mass Spectrometry Reveals Unbalanced Monomer Incorporation with Direct (Hetero)arylation Polymerization

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