The role of crystalline phase in triblock copolymer PS–PEG–PS based gas sensing materials

An unprecedented A‐B‐A type block copolymer electroactive polyurea (EPU) is designed and synthesized with tetraaniline dimer and 1,4‐phenylenediamine via an oxidative coupling, where aniline–nonamer and hexamethylene di‐urea constitute two segments. The EPU was characterized by spectral techniques such as Fourier transform infrared spectroscopy, nuclear magnetic resonance, and UV–vis spectra. The structural characterization of the prepared EPU was obtained by powder X‐ray diffraction and X‐ray photoelectron spectroscopy techniques. EPU reorganizes into core–shell microcapsules in presence of aqueous acetic acid/n‐octane interface. These microcapsules exhibited a wide range of pH responses in their absorption spectrum (UV–vis). The EPU is modified as carbon paste electrode which exhibits a remarkable electrocatalytic oxidation of ascorbic acid (AA, Vitamin C) in 0.2 M and pH 7.0 phosphate buffer solution. The carbon paste electrode is useful in sensing as low as 50 µM of ascorbic acid. This can open up new opportunities for fast, simple detection of AA providing a promising platform for sensor/biosensor designs for AA detection. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46630.

Section: Introductionmentioning

confidence: 99%

Aniline‐nonamer segmented polyurea: A facile electrocatalyst for detection of ascorbic acid

Arukula

Thota

Boga

et al. 2018

“…This result indicates that the drastic variation of electrical resistance of the composites in organic solvent vapors mainly results from the volume expansion of the amorphous phases in the matrix polymer. Li et al 14 found that the contribution of the crystalline polymer phase in CB-filled triblock copolymer PS-PEG-PS composites to electrical resistance changes of the composites in organic solvent vapors was negligible. With respect to CB/ PEG/PMMA composites, the swelling or partial dissolution of the amorphous PMMA should be the most important factor for the electrical response behavior of the composites in organic vapor.…”

Section: Resultsmentioning

confidence: 99%

Conducting property of carbon black filled poly(ethylene glycol)/poly(methyl methacrylate) composites as gas‐sensing materials

Dong¹,

Luo²,

Xie³

et al. 2007

To reveal the role of crystalline polymers in carbon black (CB) filled amorphous polymer composites and improve the mechanical properties of composite films, CB/poly(ethylene glycol) (PEG)/poly(methyl methacrylate) (PMMA) composites were synthesized by polymerization filling in this work. The electrical conductive property and response to organic solvent vapors of the composites were investigated. The composites, characterized by a relatively low percolation threshold ( 2.1 wt %), had lower resistivity than CB/PMMA composites prepared with the same method because of the different dispersion status of CB particles in the matrix polymer. The concentration and mo-lecular weight of PEG notably influenced the electrical response of the composites against organic vapors. The drastic increase in the electrical resistance of the composites in various organic vapors could be attributed mainly to the swelling of the amorphous polymer matrix in the solvent but not to that of the crystalline polymer. These findings could help us to understand the conductive mechanism and electrical response mechanism of the composites as promising gas-sensing materials.

“…In recent decades, based on resistivity variation of CPCs exposed to vapor or organic solvent stimuli, the so‐called vapor sensing and liquid sensing, that is, organic liquid stimuli‐response behaviors of CPCs were investigated more and more frequently 5–10. On the basis of these studies, CPCs have been exploited for fabrication of chemisensors,11, 12 vapor detector arrays, and “electronic noses”13, 14 capable of sensing, quantifying, and discriminating various organic vapors and solvents in chemical and petrochemical industry, environmental monitoring, and food industry.…”

Section: Introductionmentioning

confidence: 99%

Organic liquid stimuli‐response behaviors of electrically conductive microfibrillar composite with a selective conductive component distribution

Dai

Zhang

Tang

et al. 2011

This article reports the organic liquid stimuli-response behaviors of carbon black (CB)-filled electrically conductive microfibrillar poly(ethylene terephthalate) (PET)/polyethylene (PE) composite (FCMC) with CB particles selectively localized at PET microfibrils' surfaces. It was found that FCMC's thickness and CB concentration affected its responsivity significantly, a thinner FCMC film with a high CB content exhibited higher responsivity and better signals. In immersion-drying tests, FCMC displayed high and stable responsivities after six immersion-drying runs, indicating that the solvent absorption/desorption equilibrium state was achieved. After long-term immer-sion, FCMC showed obviously different organic liquid stimuli-response behaviors with faster response rate in immersion and higher terminal resistivity platform in drying, compared with samples without immersion treatment. Conductive network's microstructural changes induced by the long-term immersion and evident capillary effect, which resulted in slow evaporation of remaining solvent in FCMC's interfaces, are the reasons for the phenomenon.