High-performance wearable electronic devices with the capability of converting mechanical force into electrical energy have been gaining increasing attention for biomedical monitoring applications. We present a novel wearable piezoelectric sensor based on a poly­(vinylidene fluoride) (PVDF) nanofibrous membrane containing microporous zirconium-based metal–organic frameworks (MOFs) for arterial pulse monitoring. It is shown that the incorporation of 5 wt % of MOF greatly enhances the piezoelectric constant of the polymer fibrous mat by 3.4-fold without significant loss in its flexibility. The nanofibrous composite exhibits a peak-to-peak voltage of 600 mV under an applied force of 5 N, which is superior to many flexible pressure sensors. It is demonstrated that the enhanced piezoelectric performance of the nanofibrous composite is not only attributed to the increased degree of crystallinity and polar β phase content (75%) but also to the surface chemistry and topography of the nanofibers. Evaluations of the piezoelectric output of the sensor attached to the radial artery at normal body conditions reveal significantly better output voltage (568 ± 76 mV) and sensitivity (0.118 V/N) than nanofibrous PVDF devices for wrist pulse monitoring. The results of this work pave a new way to develop flexible piezoelectric nanofibrous sensors based on MOFs for environmentally sustainable energy generation and wearable healthcare monitoring systems.

Herein, a magnetic zirconium-based metal–organic framework nanocomposite was synthesized by a simple solvothermal method and used as an adsorbent for the removal of direct and acid dyes from aqueous solution. To enhance its adsorption performance, poly­(propyleneimine) dendrimer was used to functionalize the as-synthesized magnetic porous nanocomposite. The dendrimer-functionalized magnetic nanocomposite was characterized by field-emission scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, nitrogen adsorption/desorption isotherms, and vibration sample magnetometer. The obtained results revealed the successful synthesis and functionalization of the magnetic nanocomposite. The adsorbents exhibited good magnetic properties with high saturation magnetization and high specific surface area. The adsorption isotherms and kinetics of anionic dyes were described by the Freundlich and pseudo-second-order models, respectively. It was found that the kinetics of adsorption of both the investigated dyes by the dendrimer-functionalized magnetic composite is considerably faster than the magnetic composite under the same condition. The adsorption capacity of the dendrimer-functionalized magnetic composite for investigated direct and acid dyes was 173.7 and 122.5 mg/g, respectively, which was higher than those of the existing magnetic adsorbents. This work provides new insights into the synthesis and application of hybrid magnetic adsorbents with synergistic properties of nanoporous metal–organic frameworks and dendrimer with a large number of functional groups for the removal of organic dyes.

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In this work, the simultaneous effects of four electrospinning parameters, including solution concentration (wt%), applied voltage (kV), tip to collector distance (cm), and volume flow rate (mL/h), on contact angle (CA) of polyacrylonitrile nanofiber mat are studied. To optimize and predict the CA of electrospun fiber mat, response surface methodology (RSM) and artificial neural network (ANN) are employed and a quantitative relationship between processing variables and CA of the electrospun fibers is established. It is found that the solution concentration is the most important factor impacting the CA of electrospun fiber mat. The obtained results demonstrated that both the proposed models are highly effective in estimating the CA of electrospun fiber mat. However, more accurate results are obtained by the ANN model as compared to the RSM model. In the ANN model, the determination coefficient (R 2 ) and relative error between actual and predicted response are obtained as 0.965 and 5.94%, respectively. C

A hyperbranched, functional, water-soluble, and amine-terminated polymer is synthesized using a melt polycondensation reaction of methyl acrylate and diethylene triamine. The polymer is then characterized by FTIR and NMR spectroscopy. The polymer is soluble in some polar solvents. Poly(ethylene terephthalate) (PET) fabric as well as the fabric hydrolyzed by sodium hydroxide is treated with the polymer. A significant improvement in dyeability of PET fabric treated by the polymer with acid dye (C.I. Acid Red 114) is observed. The color characteristics of the dyed samples are evaluated using the CIELAB method. The results, obtained from dyed samples with conventional dyeing, reveal that a hyperbranched polymer, as indicated by the zeta potential measurements, offers positively charged amino groups leading to higher dye uptake. C 2013 Wiley Periodicals, Inc. Adv Polym Technol 2013, 32, 21345; View this article online at wileyonlinelibrary.com.