| 1. |
- Chen, Yujie, et al.
(författare)
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A gradient-distributed liquid-metal hydrogel capable of tunable actuation
- 2021
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Ingår i: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 421, s. 127762-
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Tidskriftsartikel (refereegranskat)abstract
- Although thermoresponsive hydrogels have numerous applications that range from soft robots, biomedical engineering, and actuators to sensors for artificial muscles, the existing hydrogel actuators undergo only unidirectional deformation under a single thermal stimulus and suffer from slow actuation and unstable interfacial adhesion in multiple layers. Herein, hydrogels containing gradient-distributed polydopamine-coated eutectic gallium-indium (PDA-EGaIn) nanodroplets in a poly(N-isopropylacrylamide) (PNIPAM) matrix and thus featuring a gradient distribution of thermal conductivity and an increased barrier towards water loss are shown to be capable of a rapid and tuneable thermoresponse. Notably, whereas hydrogels with a low content of PDAEGaIn undergo rapid one-way bending under a single thermal (45 degrees C) stimulus, those with a high content of PDAEGaIn undergo sequential bidirectional (bending) actuation. The ability of these hydrogels to undergo fast and tuneable actuation under a single thermal stimulus makes them suitable for use in grab-release instruments and soft robots.
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| 2. |
- Chen, Zhen, et al.
(författare)
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Multifunctional conductive hydrogels and their applications as smart wearable devices
- 2021
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Ingår i: Journal of materials chemistry. B. - : Royal Society of Chemistry (RSC). - 2050-750X .- 2050-7518. ; 9:11, s. 2561-2583
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Forskningsöversikt (refereegranskat)abstract
- Recently, hydrogekbased conductive materials and their applications as smart wearable devices have been paid tremendous attention due to their high stretchability, flexibility, and excellent biocompatibility. Compared with single functional conductive hydrogels, multifunctional conductive hydrogels are more advantageous to match various demands for practical applications. This review focuses on multifunctional conductive hydrogels applied for smart wearable devices. Representative strategies for conduction of hydrogels are discussed firstly: (1) electronic conduction based on the conductive fillers and (2) ionic conduction based on charged ions. Then, the common and intensive research on multiple functionahties of conductive hydrogels, such as mechanical properties, conductive and sensory properties, anti-freezing and moisturizing properties, and adhesion and self-healing properties is presented. The applications of multifunctional conductive hydrogels such as in human motion sensors, sensory skins, and personal healthcare diagnosis are provided in the third part. Finally, we offer our perspective on open challenges and future areas of interest for multifunctional conductive hydrogels used as smart wearable devices.
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| 3. |
- Liu, Yujie, et al.
(författare)
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Semi-empirical treatment of ionophore-assisted ion-transfers in ultrathin membranes coupled to a redox conducting polymer
- 2021
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Ingår i: Electrochimica Acta. - : Elsevier BV. - 0013-4686 .- 1873-3859. ; 388, s. 138634-
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Tidskriftsartikel (refereegranskat)abstract
- Applying spectroelectrochemistry to all-solid-state electrodes composed of poly(3-octylthiophene) (POT) and an ultrathin ion-selective membrane on top, it is possible to monitor the dynamic charge transfer (CT) in POT when this event is coupled to ion transfers (ITs) promoted by the absence/presence of a se-lective ionophore in the membrane. Herein, we report on a combination of empirical and theoretical ev-idence revealing that different molar ratios of the ionophore and the cation exchanger in the membrane result in the modulation of non-assisted and assisted ITs of different stoichiometries. This occurs upon the same anodic voltammetric scan. The use of the developed theory together with Sigmoidal & minus;Boltzmann fittings of the experimental dynamic absorbance observed in the POT film permits calculating voltammo-grams with different ITs. An easy semi-empirical treatment additionally provides the calculation of bind-ing constants related to the assisted transfers. Furthermore, the approach is suitable for both preferred and non-preferred ions by the ionophore, which additionally leads to the estimation of the selectivity profile of the POT-membrane system. The extra discovery about the number of electrons associated to the CT in the POT film is expected to propitiate further research towards maximizing peak resolution in the voltammetric experiments. In this context, the developed theory would help in future steps to-wards the prediction of voltammetric responses for multi-ionophore membranes backside contacted with new redox materials, prospecting hence new electrodes for multi-ion detection with optimized analytical features.
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| 4. |
- Wang, Hui, et al.
(författare)
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Promotion of NH3-SCR activity by sulfate-modification over mesoporous Fe doped CeO2 catalyst : Structure and mechanism
- 2021
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Ingår i: Journal of Hazardous Materials. - : ELSEVIER. - 0304-3894 .- 1873-3336. ; 414
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Tidskriftsartikel (refereegranskat)abstract
- The mesoporous Fe doped CeO2 catalyst after modifying organic sulfate functional groups show an excellent activity with above 80% NOx conversion in a temperature range of 250-450 degrees C. These organic-like sulfate groups bound to the Fe-O-Ce species leads to the strong electron interaction between Fe3+-O-Ce4+ species and sulfate groups, which modifies the acidity and redox properties of catalyst. The strong ability of (SO)-O-=/S-O in sulfate groups to accommodate electrons from a basic molecule is a driving force in the generation of acidic properties, and thus promotes to produce new Bronsted acid sites. The bondage of Fe-O-Ce species obviously inhibits the creation of thermostable bidentate NO3- species. Besides, the redox cycles between Fe3+ and Ce4+ are disrupted, thus inhibiting NH3 oxidation at medium-high temperatures and resulting in the increase of NOx conversion. Furthermore, the in situ DRIFTS results show that for the fresh samples, the coordinate NH3 reacts not only with NO3 through L-H mechanism, but also with oxygen species to form NOx. Differently for sulfated sample, the coordinate NH3 might react with achieved NO2 instead of the oxygen species through E-R mechanism, meanwhile the NH4+ could react with the NO3- species through L-H mechanism.
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| 5. |
- Wang, Qianyu, et al.
(författare)
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Electrochemical biosensor for glycine detection in biological fluids
- 2021
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Ingår i: Biosensors & bioelectronics. - : Elsevier BV. - 0956-5663 .- 1873-4235. ; 182
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Tidskriftsartikel (refereegranskat)abstract
- We present herein the very first amperometric biosensor for the quantitative determination of glycine in diverse biological fluids. The biosensor is based on a novel quinoprotein that catalyzes the oxidation of glycine with high specificity. This process is coupled to the redox conversion of Prussian blue in the presence of hydrogen peroxide originating from the enzymatic reaction. The optimized tailoring of the biosensor design consists of the effective encapsulation of the quinoprotein in a chitosan matrix with the posterior addition of an outer Nafion layer, which is here demonstrated to suppress matrix interference. This is particularly important in the case of ascorbic acid, which is known to influence the redox behavior of the Prussian blue. The analytical performance of the biosensor demonstrates fast response time (<7 s), acceptable reversibility, reproducibility, and stability (<6% variation) as well as a wide linear range of response (25?500 ?M) that covers healthy (and even most unhealthy) physiological levels of glycine in blood/serum, urine and sweat. A total of 6 real samples from healthy patients and animals were analyzed: two serum, two urine and two sweat samples. The results were validated via commercially available fluorescence kit, displaying discrepancy of less than 9% in all the samples. The unique analytical features and effortless preparation of the new glycine biosensor position it at the forefront of current technologies towards decentralized clinical applications and sport performance monitoring.
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