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Polyaniline/poly(methylmethacrylate) (PANI/PMMA) microfiber coating were successfully deposited on carbon steel by electro-spinning and drop-cast methods, and their corrosion protection performances were evaluated in H2SO4. The results show the corrosion protection property of coating is outstanding with a certain amount of PANI (25 wt.%), especially for electro-spun coating. The reason of superior corrosion protection function of PANI electro-spun coating was investigated, which is primarily attributed to its better barrier protection, behaved as a lower porosity and enhanced adhesive ability. The outstanding corrosion protection performance of PANI/PMMA microfiber coatings encourages the wider application of electro-spun coatings in the corrosion protection area.

Cathodic polarization antifouling has attracted attention because of environment-friendly property. We have developed a conductive PPy/resin coating with good electrochemical antifouling effects. However, its conductivity should be further improved to save the electric energy. In this work, a conductive Ag@PPy/resin composite was synthesized. Compared to PPy/resin coating, its conductivity was increased by 6 times, besides, its stability and 2e− oxygen reduction reaction (ORR) activity were obviously enhanced. And the antifouling effect under smaller cathodic voltage (−0.3 V) is improved, increasing the anti-fouling efficiency.

Cathodic polarization antifouling deserves attention because of its environmentally friendly nature and good sustainability. It has been proven that cathodic voltages applied on metal substrates exhibit outstanding antifouling effects. However, most metals immersed in marine environment are protected by insulated anticorrosive coatings, restricting the cathodic polarization applied on metals. This study developed a conducting polypyrrole (PPy)/acrylic resin coating (σ = 0.18 Scm−1), which can be applied in cathodic polarization antifouling. The good stability and electro-activity of PPy in the negative polarity zone in alkalescent NaCl solution were verified by linear sweep voltammetry (LSV), chronoamperometry (CA), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), demonstrating the feasibility of PPy as cathodic polarization material. Furthermore, the antifouling effects of PPy/acrylicresin coating on 24-h old Escherichia coli bacteria (E. coli) which formed on PPy/acrylic resin-coated plastic plate were measured under different cathodic potentials and treatment time, characterized by fluorescent microscope. The results suggest that at cathodic potential around −0.5 V (vs. saturated calomel electrode (SCE)), there was little trace of attached bacteria on the substrate after 20 min of treatment. PPy/acrylicresin-coated substrates were also subjected to repeated cycles of biofilm formation and electrochemical removal, where high removal efficiencies were maintained throughout the total polarization process. Under these conditions, the generation of hydrogen peroxide is believed to be responsible for the antifouling effects because of causing oxidative damage to cells, suggesting the potential of the proposed technology for application on insulated surfaces in various industrial settings.

Cathodic voltage applied to metal substrata has been proven to exhibit useful antifouling properties due to the generation of H2O2, where the metal substratum is used as a cathode in the process. However, most metals immersed in a marine environment are protected by insulating (anticorrosive) coatings, restricting the cathodic polarization that can be applied to the metal. In this work, polyaniline-polymethyl methacrylate was found to have good stability and low background current density, as measured by linear sweep voltammetry (LSV), chronoamperometry (CA) and cyclic voltammetry (CV), suggesting potential for use of PANI-PMMA as a cathode material. The antifouling effects of the PANI-PMMA coating on 24-h-old Escherichia coli bacteria (E. coli) were measured under different cathodic potentials and different polarization times; the outstanding antifouling effect was verified by fluorescence microscopy. Keywords: PANI-PMMA, Stability, Cathode material, Cathodic polarization antifouling

This study explores the feasibility of polyaniline-TiO2 coatings for photocathodic antifouling: antibacterial effect. PANI-TiO2 composites were prepared by chemical polymerization of polyaniline (PANI) in the presence of anatase TiO2, followed by dispersion of the resulting PANI-TiO2 composite in an acrylic resin for coating applications. The incorporation of PANI resulted in sensitization of the TiO2 to visible light, resulting in efficient electron and hole transfer between the PANI and TiO2 components. Under UV–vis illumination, the balanced potential of the PANI-TiO2 coating on 316 L stainless steel in a 3.5 wt.% NaCl solution was lowered to −0.4 V (vs. a saturated calomel electrode), sufficient to achieve cathodic protection of the stainless steel. The PANI-TiO2 coating also possessed good antimicrobial activity under UV–vis illumination for 30 min (efficiency > 70%). The antibacterial properties of the PANI-TiO2 coating can be attributed to the generation of H2O2 or other reactive oxygen species through photovoltaic effects, which cause oxidative damage to E. coli cells. This work confirms the feasibility of using PANI-TiO2 coatings to prevent biofouling (especially for fouling raised by the bacterial) of steels in marine environments.

A facile fabrication strategy via electrospinning and followed by in situ polymerization to fabricate a patterned, highly stretchable, and conductive polyaniline/poly(vinylidene fluoride) (PANI/PVDF) nanofibrous membrane is reported. Owing to the patterned structure, the nanofibrous PANI/PVDF strain sensor can detect a strain up to 110%, for comparison, which is 2.6 times higher than the common nonwoven PANI/PVDF mat and much larger than the previously reported values (usually less than 15%). Meanwhile, the conductivity of the patterned strain sensor shows a linear response to the applied strain in a wide range from 0% to about 85%. Additionally, the patterned PANI/PVDF strain sensor can completely recover to its original electrical and mechanical values within a strain range of more than 22%, and exhibits good durability over 10,000 folding-unfolding tests. Furthermore, the strain sensor also can be used to detect finger motion. The results demonstrate promising application of the patterned nanofibrous membrane in flexible electronic fields.

The coal dressing method of heavy medium has many advantages, as follows, the strong adaptability on coal quality of raw coal ,high precision of separation, the wide grade range, Craft system simplification, easy to realize the automation and other advantages, which have rapid development trend both at home and abroad. Heavy medium density automatic control system is one of the most important key, that height and stability play a decisive role on the quality of products and production rate for coal production process. In this article, the heavy medium density is accurate measured with the ultrasonic attenuation theory, he law of attenuation is analyzed in the heavy medium density liquid, the relationship between the density and sound attenuation is summarized. And the closed loop automatic control is realized based on which and the separation efficiency is improved, the cost is saved.

Seedlings of Citrus sinensis (L.) Osbeck were supplied with boron (B)-deficient (without H3BO3) or -sufficient (10 µM H3BO3) nutrient solution for 15 weeks. We identified 54 (38) and 38 (45) up (down)-regulated cDNA-AFLP bands (transcript-derived fragments, TDFs) from B-deficient leaves and roots, respectively. These TDFs were mainly involved in protein and amino acid metabolism, carbohydrate and energy metabolism, nucleic acid metabolism, cell transport, signal transduction, and stress response and defense. The majority of the differentially expressed TDFs were isolated only from B-deficient roots or leaves, only seven TDFs with the same GenBank ID were isolated from the both. In addition, ATP biosynthesis-related TDFs were induced in B-deficient roots, but unaffected in B-deficient leaves. Most of the differentially expressed TDFs associated with signal transduction and stress defense were down-regulated in roots, but up-regulated in leaves. TDFs related to protein ubiquitination and proteolysis were induced in B-deficient leaves except for one TDF, while only two down-regulated TDFs associated with ubiquitination were detected in B-deficient roots. Thus, many differences existed in long-term B-deficiency-responsive genes between roots and leaves. In conclusion, our findings provided a global picture of the differential responses occurring in B-deficient roots and leaves and revealed new insight into the different adaptive mechanisms of C. sinensis roots and leaves to B-deficiency at the transcriptional level.