Environmentally friendly methodologies of nanostructure synthesis

Environmentally friendly synthetic methodologies have gradually been implemented as viable techniques in the synthesis of a range of nanostructures. In this work, we focus on the application of green-chemistry principles to the synthesis of complex metal oxide and fluoride nanostructures. In particular, we describe advances in the use of the molten-salt synthetic methods, hydrothermal protocols, and template-directed techniques as environmentally sound, socially responsible, and cost-effective methodologies that allow us to generate nanomaterials without the need to sacrifice sample quality, purity, and crystallinity, while allowing control over size, shape, and morphology.     

等离子体预处理制备抗菌-特殊润湿性除油型棉织物

为实现特殊润湿性材料的规模化生产,构筑长效、耐久、稳定的特殊浸润性油水分离产品,以棉织物网膜为基材,对其进行了等离子体预处理与超疏水性界面构建的研究。即将聚氨酯胶黏剂(PU)与合成的Ag@SiO2球形颗粒分别配制成涂剂A与涂剂B,采用简单的交替高压喷涂技术与疏水改性处理,在棉织物表面构建了强健的微纳二级粗糙结构,继而获得超疏水性生物质网膜材料。系统地研究了等离子体预处理基材距离、电压、喷涂次数等对基材表面粗糙度的作用规律,并对合成产品在抗菌防护与油水分离领域进行了应用探索。结果,该产品是一种优异的特殊润湿性除油型生物质基网膜材料,能够有效地实现油水分离应用,并防止病菌附着。     

One-step anti-superbug finishing of cotton textiles with dopamine-menthol

In this work, the one-step stereochemical antimicrobial finishing of cotton textiles(CT) was achieved by the oxidative copolymerization of a dopamine-menthol derivative(DAM) and dopamine(DA). The obtained DAM-modified CT(P(DAM-co-DA)-CT) exhibited broad-spectrum microbial anti-adhesion properties against bacteria(E. coli and P. aeruginosa), including superbugs(MRSA and VREF), and fungi(A.niger, A. flavus, M. racemosus and P. chrysogenum). Because of its unique stereochemical antimicrobial mechanism, the obtained P(DAM-co-DA)-CT is a non-releasing antimicrobial material that causes no skin sensitization and exhibits good biocompatibility. The coating was also found to enhance the UVresistant and mechanical properties of the CT. Furthermore, it displayed durable washing fastness and antimicrobial properties after the endurance of 30 laundering cycles. The observed achievements provide a broader understanding of stereochemical antimicrobial surfaces and endow this method with wider applications.     

Superhydrophobic and ultraviolet-blocking cotton textiles

Cotton textile was coated with ZnO@SiO(2) nanorods in order to obtain superhydrophobic and ultraviolet (UV)-blocking properties. The coating process was conducted in mild conditions, which involved the low-temperature preparation of ZnO seeds, hydrothermal growth of ZnO nanorods, bioinspired layer-by-layer deposition of a SiO(2) shell on the surface of ZnO nanorods, and hydrophobic modification of ZnO@SiO(2) nanorods with octadecyltrimethoxysilane. Despite the highly curved morphology of cotton fibers, the ZnO@SiO(2) nanorods coated the textile densely and uniformly. The treated cotton textile was found to have a large UV protection factor (UPF = 101.51) together with UV-durable superhydrophobicity, as determined by contact-angle measurement under long-term UV irradiation. The good UV-blocking property can be ascribed to the high UV absorbance and scattering properties of ZnO nanorods, and the UV-durable superhydrophobicity is a result of suppression of the photoactivity of ZnO nanorods by a SiO(2) shell.     

Environmentally friendly efficient one-pot esterification of cyclohexane with CuO-promoted sulfated zirconia

The production of dibutyl phthalate directly from oxidation and esterification of cyclohexane, catalyzed by CuO-modified sulfated zirconia (SZCu) by one-pot under mild condition, was studied. The esterification reaction process was monitored by UV-vis spectra and the distribution of the products was analyzed by gas chromatograph-mass spectrometry (GC-MS). The result revealed that the SZCu catalyst was efficient in the direct oxidation and esterification of cyclohexane to ester. The selectivity for ester (dibutyl phthalate) can reach up to 72.2 wt.%, and the yield of ester was 29.5 wt.%. The esterification reaction, that offers several advantages such as usage of environmental friendly oxidant, simple work-up procedure, no-solvent conditions, short reaction times, easy recovery and reusability of the catalyst, is necessary for chemosynthesis industry from the environment standpoint. The regeneration property of SZCu was also tested in this work.     

Preparation of superhydrophobic surfaces on cotton textiles

Abstract

Superhydrophobic surfaces were fabricated by the complex coating of silica nanoparticles with functional groups onto cotton textiles to generate a dual-size surface roughness, followed by hydrophobization with stearic acid, 1H, 1H, 2H, 2H-perfluorodecyltrichlorosilane or their combination. The wettability and morphology of the as-fabricated surfaces were investigated by contact angle measurement and scanning electron microscopy. Characterizations by transmission electron microscopy, Fourier transformation infrared spectroscopy, and thermal gravimetric analysis were also conducted.     

Preparation of superhydrophobic surfaces on cotton textiles

Superhydrophobic surfaces were fabricated by the complex coating of silica nanoparticles with functional groups onto cotton textiles to generate a dual-size surface roughness, followed by hydrophobization with stearic acid, 1H, 1H, 2H, 2H-perfluorodecyltrichlorosilane or their combination. The wettability and morphology of the as-fabricated surfaces were investigated by contact angle measurement and scanning electron microscopy. Characterizations by transmission electron microscopy, Fourier transformation infrared spectroscopy, and thermal gravimetric analysis were also conducted.     

Environmentally friendly catalytic combustion of gaseous fuel to heat greenhouses

Data on the study of thermally stable manganese oxide catalysts for deep oxidation of lean CH₄ and propane–butane mixtures in air into CO₂ are presented in the paper. New approaches to the synthesis of polyoxide catalysts based on Mn, modified with rare earth elements (La, Ce) and alkaline earth elements (Ba, Sr) when its supporting from nitrate solutions onto the alumina granules stabilized with 2 % Ce were used in the preparation of catalysts. Polyoxide thermally stable (up to 1473 K) high-performance Mn-containing catalyst for deep oxidation of CH₄ and propane–butane in gas-air mixture was developed. Prototype of the catalytic heat generator for environmentally friendly burning of methane and propane–butane mixture was created. Experienced tests of the catalytic heat generator for heating of greenhouses were performed and carbon dioxide fertilizing of plants by combustion products of propane–butane mixture was carried out.     

Review Environmentally friendly coatings using carbon dioxide as the carrier medium

The use of supercritical or liquid carbon dioxide as a medium for delivering coating systems is attracting much interest because of concerns over the environmental effects of volatile organic compound (VOC) emissions from conventional coatings. Significant reductions in VOC emissions can be achieved by replacing some or all of the organic solvent by CO₂ in spray coatings. Technical and commercial benefits are also claimed for these systems, including improved coating efficiency and operating cost savings. In this review, the range of current and potential applications achievable using CO₂-based coatings is discussed. In addition to spray coatings onto a variety of substrate surfaces, CO₂ processes can be used to produce controlled particle size powders for use in powder coatings and also for the coating of preformed particles such as metal powders and pharmaceuticals for controlled release in drug delivery. Use of CO₂ in spin coating and microlithography offers the potential for significant waste reduction. Specific substrates where use of CO₂ can be beneficial include the treatment of building stone and wood treatment. CO₂ can aid surface impregnation of substrates because of its high diffusivity and the potential for substrate swelling.     

Dyeable electroconductive cotton wrapped CNT yarn for multifunctional textiles

Journal of Materials Science - Conductive fiber plays increasingly important role in the field of multifunctional textile and smart clothing for the signal/power transmission, electrothermal...     

Environmentally friendly aqueous solution synthesis of hierarchical CaWO4 microspheres at room temperature

An environmentally friendly route for the synthesis of hierarchical CaWO4 microspheres with novel morphology at room temperature has been successfully developed. CaCl2 and Na2WO4 were used as reaction regents, and distilled water was used as an environmentally friendly solvent. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and photoluminescence spectroscopy. This green wet-chemical route provides a simple, one-step, low-cost approach for the large-scale synthesis of hierarchical CaWO4 microspheres with relatively uniform diameters of 3-6 microm. The hierarchical microspheres are built up with numerous nanorods with an average diameter of 50 nm, which are radially oriented to the microsphere center. SEM observations of different intermediates indicate the possible growth process, in which the hierarchical structure growth is from nuclei through kayak-like, rod-like, peanut-like, dumbbell-like, and peach-like structures to final microspheres, via "self-assembled preferential end growth" of kayak-like particles in aqueous solution. The hierarchical CaWO4 microspheres exhibit a strong, broad blue emission peak of 412 nm.     

抗菌疏水棉织物的制备及性能研究

将卤胺化合物GHAPA和无氟疏水剂REPELLAN FF共浴整理棉织物,通过轧烘焙工艺制备出一种具有抗菌疏水性能的棉织物。探究了焙烘温度、浓度对织物含氯量和接触角的影响,确定出最佳整理工艺。采用SEM、FT-IR对整理后的棉织物进行表征,测试分析了整理后棉织物的强力、疏水性及抗菌性能。结果表明经过整理后织物的疏水角能够达到136°,具有良好的疏水性能;抗菌测试结果表明氯化后的棉织物具有优异的抗菌性能,在5 min内可杀死全部金黄色葡萄球菌,30 min内可杀死全部大肠杆菌。     

Environmentally friendly growth of single-crystalline K2Ti6O13 nanoribbons from KCl flux

Single-crystalline K₂Ti₆O₁₃ nanoribbons with typical width ranging from one hundred nanometers to a few hundred nanometers and length up to tens of microns were prepared from KCl flux. The nanoribbons were characterized by a range of methods including X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, selected area electron diffraction and high-resolution transmission electron microscopy. Ultraviolet–visible experiments showed that the K₂Ti₆O₁₃ nanoribbons were wide-band semiconductors with a band width E_g = 3.4 eV. The mechanism of one-dimensional growth of the nanoribbons was attributed to the oriented attachment mechanism.     

Characterization and antibacterial properties of nanoboron powders and nanoboron powder coated textiles

The antibacterial properties of boron-containing compounds are well known although there are limited studies available on the pure boron nanoparticles. In this paper, nanoboron particles are characterized in terms of their particle size, shape, stability and surface charge before and after their application onto textile surfaces to study their impact on bacterial activity. It was observed that the boron nanoparticles are effective in limiting the bacterial growth of both Gram-negative and positive species without requiring any stimulation to initiate the antibacterial action. In addition to the antibacterial functionality evaluation of the free boron nanoparticles, nanoboron coated textiles were also characterized and determined to change the wettability and surface charge of the textiles with a variable antimicrobial response to the different species. Consequently, we propose pure nanoboron as a new anti-bacterial agent that can function without external stimulation.     

High-efficiency antibacterial and anti-mildew properties under self-assembly: An environmentally friendly nanocomposite

Leather is easy to breed colonies or mildew during the storage process, destroy the fiber structure, and affect human health. The antibacterial treatment of leather is usually through adding antimicrobials during the re-tanning process. However, traditional leather antibacterial agent has benzene, sulfur and other harmful substances. In recent years, they have been banned in the process of making leather. In this study, poly(dimethyl diallyl ammonium chloride-methacrylic acid)/silver deposited ZnO composite was prepared by in-situ method and used in leather re-tanning process. The self-assembly behavior occured between silver deposited ZnO and polymer with the flower-like morphology formed via the situ polymerization. After re-tanning process, Ag/ZnO and N⁺ in the composite provide leather with efficient antibacterial, anti-mildew and physical properties. Meanwhile, there were no harmful substances in the composite compared with traditional leather antibacterial agent, which was a kind of “friendly” antimicrobial material.     

Superhydrophobic surfaces on cotton textiles by complex coating of silica nanoparticles and hydrophobization

By the complex coating of amino- and epoxy-functionalized silica nanoparticles on epoxy-functionalized cotton textiles to generate a dual-size surface roughness, followed by hydrophobization with stearic acid, 1H,1H,2H,2H-perfluorodecyltrichlorosilane, or their combination, superhydrophobic surfaces were prepared. The static water contact angle of the most superhydrophobic sample as prepared reaches 170° for a 5 μL droplet. The wettability and morphology were investigated by contact angle measurement and scanning electron microscopy. Characterizations by Fourier transformation infrared spectroscopy, and thermal gravimetric analysis were also conducted.