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Delamination due to an inferior adhesion between reinforcement material and matrix in carbon fiber-reinforced thermoplastic (CFRTP) composites is a crucial problem to be solved. To this end, this study aims to overcome poor wettability between reinforcing phase, i.e., carbon fiber (CF), and thermoplastic matrix, i.e., polyetherether ketone (PEEK). Herein, CF's surface was tailored by application of different polymeric sizing agents which have different chemical structures. Morphology and topology analyses were performed by Scanning Electron Microscope and 3D laser scanning, respectively. Later, a variety of wettability results were obtained by the sessile drop method used in Contact Angle (CA) measurements for CFs throughout application of each sizing agent applied by dip coating. Sizing materials were designed such that the chemical structure of CF's surface could exhibit compatibility with the matrix itself. Consequently, complete wettability (CA: 0°) was achieved for CFs sized by HPEEK (CF/hydroxylated PEEK (HPEEK)) and the surface free energy (SFE) of CF was enhanced from 5.43 to 72.8 mJ/m2 while the SFE of the PEEK matrix is 40.1 mJ/m2. Moreover, sizing by HPEEK improved the average surface roughness of CF by 32% which enables optimized adhesion. Afterward, repetitive tensile tests were carried out to observe effects of improved interfacial interlocking on the mechanical properties of the final CFRTP composite. Stress–strain curves revealed that the tensile strength of CFRTP improved from 473 to 508 MPa through the sizing of CF by HPEEK whereas pristine PEEK has a much smaller tensile strength (98 MPa) than the aforementioned CF-reinforced composites. The sizing of carbon fiber's surface by HPEEK resulted in an enhanced adhesion with the PEEK matrix. Since the chemical structure and physical properties of sizing agent and matrix are compatible, potential debonding between them was eliminated. Thus, the improved wettability led to a substantial increase in the mechanical strength of the final TP composite. [ABSTRACT FROM AUTHOR]

Here we report the preparation of water-dispersible glycosylated poly(2,5′-thienylene)porphyrin based nanoparticles by a nanoprecipitation method and demonstrate the application of these nanoparticles in antibacterial photodynamic therapy. The diameter of the nanoparticles is in the range of 50–80 nm and the resulting nanoparticles are stable in water without precipitation at least for a month. They have high singlet oxygen efficiency and display light-triggered biocidal activity against both Gram negative bacteria (Escherichia coli, E. coli) and Gram positive bacteria (Bacillus subtilis, B. subtilis). Upon white light irradiation for 10 min with a flux of 22 mW cm−2 of the E. coli suspension incubated with NPs (18 μg mL−1), a killing efficiency of 99% is achieved, whereas in the dark the effect is recorded as only around 8%. [ABSTRACT FROM AUTHOR]

In the present work, we describe an efficient filter-based microextraction method with a proper sample clean-up for the simple determination of the banned Sudan dyes (I, II, III, and IV) in the foodstuff and water samples. The method is based upon the dispersion of a low-toxic solidifiable organic solvent (1-undecanol, 75 μL) into an aqueous sample solution and utilization of a syringe filter for the emulsion breaking. This syringe filter with a nylon membrane is compatible with a broad range of solvents and thus is ideal for the rapid filtration of most aqueous and organic solutions. Hence, along with the passage of a mixture of an aqueous sample solution and an organic solvent through the membrane, fine droplets of the extractant solvent are aggregated, separated from the aqueous sample solution. By implementing this simple method, the overall extraction time is just 3-4 min; it is environmentally friendly and centrifuge-free, and it provides a high sample clean-up by filtration of the acceptor phase. The parameters influencing the extraction efficiency including the type and volume of the extraction solvent, pH, ionic strength, and number of extractions are thoroughly examined and optimized. Under the optimal experimental conditions, the proposed method provided a good linearity in the range of 1.0-1500 ng mL−1, good extraction repeatabilities (relative standard deviations below 8.9%, n = 5), low limits of detection (0.2-0.7 ng mL−1), and enrichment factors of 105-138. [ABSTRACT FROM AUTHOR]

A simple, fast, and sensitive method for speciation and determination of As (III, V) and Hg (II, R) in human blood samples based on ionic liquid-dispersive liquid-liquid microextraction (IL-DLLME) and flow injection hydride generation/cold vapor atomic absorption spectrometry (FI-HG/CV-AAS) has been developed. Tetraethylthiuram disulfide, mixed ionic liquids (hydrophobic and hydrophilic ILs) and acetone were used in the DLLME step as the chelating agent, extraction and dispersive solvents, respectively. Using a microwave assisted-UV system, organic mercury (R-Hg) was converted to Hg(II) and total mercury amount was measured in blood samples by the presented method. Total arsenic content was determined by reducing As(V) to As(III) with potassium iodide and ascorbic acid in a hydrochloric acid solution. Finally, As(V) and R-Hg were determined by mathematically subtracting the As(III) and Hg(II) content from the total arsenic and mercury, respectively. Under optimum conditions, linear range and detection limit (3σ) of 0.1-5.0 μg L−1 and 0.02 μg L−1 for As(III) and 0.15-8.50 μg L−1 and 0.03 μg L−1 for Hg(II) were achieved, respectively, at low RSD values of < 4 % (N = 10). The developed method was successfully applied to determine the ultratrace amounts of arsenic and mercury species in blood samples; the validation of the method was performed using standard reference materials. [ABSTRACT FROM AUTHOR]