Wettability of Graffiti Coatings by Green Nanostructured Fluids.

Green nanostructured fluids (GNFs), specifically water-in-oil nanoemulsions (w/o NEs), were investigated as professional "brush on, wipe off" nanodetergents for the effective removal of various challenging graffiti coatings. The efficacy of the advanced nanodetergents in eradicating resilient graffiti coatings was evaluated using various methods to assess the surface properties of forming graffiti coatings. The surface properties of these coatings were examined by assessing their wettability by water, surface free energy, and topography to obtain information on the intermolecular interactions with the nanodetergent during the wetting and graffiti removal process. Our findings revealed significant variations in the coating removal rate and efficacy of green nanostructured fluids, which are stabilized using surfactants derived from saccharides or amino acids. A water-in-oil nanoemulsion, stabilized by caprylyl/capryl glucoside, demonstrated exceptional efficiency at cleaning graffiti paints based on alkyd resin and containing various additives such as nitrocellulose or bitumen, from any hard surface within a short time period. However, a w/o NE, stabilized by sodium cocoyl glycinate, also showed effective removal of graffiti paints containing durable bitumen, albeit at a slower rate on. These green nanostructured fluids can be used as specific nanodetergents for the comprehensive removal of various graffiti coatings, but require a specified action time to prevent damage to the original substrate beneath the paint coating.

Multiheaded Cationic Surfactants with Dedicated Functionalities: Design, Synthetic Strategies, Self-Assembly and Performance.

Contemporary research concerning surfactant science and technology comprises a variety of requirements relating to the design of surfactant structures with widely varying architectures to achieve physicochemical properties and dedicated functionality. Such approaches are necessary to make them applicable to modern technologies, such as nanostructure engineering, surface structurization or fine chemicals, e.g., magnetic surfactants, biocidal agents, capping and stabilizing reagents or reactive agents at interfaces. Even slight modifications of a surfactant's molecular structure with respect to the conventional single-head-single-tail design allow for various custom-designed products. Among them, multicharge structures are the most intriguing. Their preparation requires specific synthetic routes that enable both main amphiphilic compound synthesis using appropriate step-by-step reaction strategies or coupling approaches as well as further derivatization toward specific features such as magnetic properties. Some of the most challenging aspects of multicharge cationic surfactants relate to their use at different interfaces for stable nanostructures formation, applying capping effects or complexation with polyelectrolytes. Multiheaded cationic surfactants exhibit strong antimicrobial and antiviral activity, allowing them to be implemented in various biomedical fields, especially biofilm prevention and eradication. Therefore, recent advances in synthetic strategies for multiheaded cationic surfactants, their self-aggregation and performance are scrutinized in this up-to-date review, emphasizing their applications in different fields such as building blocks in nanostructure engineering and their use as fine chemicals.

Antimicrobial action and chemical and physical properties of CuO-doped engineered cementitious composites.

CuO nanoparticles (NPs) were added to cement matrices in quantities of 0.25, 0.50 and 1.00 wt% to inhibit the growth of Gram-positive (Bacillus cereus, Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa, Escherichia coli) bacteria. It was shown that CuO NPs, in all tested concentrations, improved the antibacterial properties of the cement matrix. Nevertheless, the best mechanical, structural and durability properties were obtained for cement composites doped with CuO NPs at 0.25 wt%. Larger amounts of NPs caused a decrease in all parameters relative to the reference mortar, which may be the result of a slight change in the porosity of the composite microstructure. For 0.50 wt% CuO NPs, a slight increase in the volume of micropores in the cement matrix was observed, and an increased number of larger pores was confirmed by non-invasive computed tomography (CT). The reduction in the mechanical parameters of composites with 0.50 and 1.00 wt% CuO NPs may also be due to the slower hydration of the cement binder, as confirmed by changes in the heat of hydration for these configurations, or agglomeration of NPs, especially for the 1.00 wt% concentration, which was manifested in a decrease in the plasticity of the mortars.

Surface Properties of Graffiti Coatings on Sensitive Surfaces Concerning Their Removal with Formulations Based on the Amino-Acid-Type Surfactants.

Water-in-oil (w/o) nanoemulsions stabilized with amino acid surfactants (AAS) are one example of nanotechnology detergents of the "brush on, wipe off"-type for removing graffiti coatings from different sensitive surfaces. The high-pressure homogenization (HPH) process was used to obtain the nanostructured fluids (NSFs), including the non-toxic and eco-friendly components such as AAS, esterified vegetable oils, and ethyl lactate. The most effective NSF detergent was determined by response surface methodology (RSM) optimization. Afterwards, several surface properties, i.e., topography, wettability, surface free energy, and the work of water adhesion to surfaces before and after their coverage with the black graffiti paint, as well as after the removal of the paint layers by the eco-remover, were determined. It was found that the removal of graffiti with the use of the NSF detergent is more dependent on the energetic properties and microporous structure of the paint coatings than on the properties of the substrates on which the layers were deposited. The use of NSFs and knowledge of the surface properties could enable the development of versatile detergents that would remove unwanted contamination from various surfaces easily and in a controlled way.

Formulation of Environmentally Safe Graffiti Remover Containing Esterified Plant Oils and Sugar Surfactant.

The removal of graffiti or over-painting requires special attention in order to not induce the surface destruction but to also address all of the important eco-compatibility concerns. Because of the necessity to avoid the use of volatile and toxic petroleum-based solvents that are common in cleaning formulations, much attention has recently been paid to the design of a variety of sustainable formulations that are based on biodegradable raw materials. In the present contribution we propose a new approach to graffiti cleaning formulations that are composed of newly synthesized green solvents such as esterified plant oils, i.e., rapeseed oil (RO), sunflower oil (SO), or used cooking oil (UCO), ethyl lactate (EL), and alkylpolyglucosides (APGs) as surfactants. Oil PEG-8 ester solvents were synthesized through the direct esterification/transesterification of these oils using monobutyltin(IV) tris(2-ethylhexanoate) and titanium(IV) butoxide catalysts under mild process conditions. The most efficient formulations, determined by optimization through the response surface methodology (RSM) was more effective in comparison to the reference solvents such as the so-called Nitro solvent (denoting a mixture of toluene and acetone) and petroleum ether. Additionally, the optimal product was found to be effective in removing graffiti from glass, metal, or sandstone surfaces under open-field conditions in the city of Wroclaw. The performed studies could be an invaluable tool for developing future green formulations for graffiti removal.

Optimization of Ultrasound-Assisted Extraction of Functional Food Fiber from Canadian Horseweed (Erigeron canadensis L.).

Much attention has been recently paid to the design of sustainable processes for the production of functional food additives based on renewable resources. Thus, methods for incorporation of green techniques in treatment of undeveloped biomass, resulting in value-added bioproducts, are in great demand. We focus here on the biological activity and chemical properties of Erigeron canadensis (horseweed) functional food fiber, which can be strongly affected by the extraction procedure employed. In the present contribution, we report on an attempt to introduce a sustainable and energy-efficient ultrasound-assisted extraction process, followed by a multistep purification procedure, resulting in a macromolecular plant-derived anticoagulant agent. The most efficient ultrasound-assisted process was determined by optimization through the response surface methodology I-optimal design (24). A comparison with the conventional procedure for retrieval of horseweed biomacromolecules revealed that the optimized ultrasound-assisted extraction was more sustainable, with the cumulative energy demand being 38% lower (12.2 MJ), 6.6 times reduced water consumption (3.5 L), and 1.2 times shorter (41 h) total processing time. Moreover, the optimal ultrasound-assisted extraction process-purified food fiber turned out to be a better anticoagulant agent by 57%, compared to a conventional product, and was a more selective indirect inhibitor of the human Xa coagulation factor.

Effect of various extraction methods on the structure of polyphenolic-polysaccharide conjugates from Fragaria vesca L. leaf.

The purpose of this study was to compare the application of several extraction methods, including cold extraction (CAE), hot extraction (HAE), ultrasonic-assisted extraction (UAE), and microwave-assisted extraction (MAE), all carried out in 0.1 M NaOH, under their respective best parameters, for obtaining products from leaf of Fragaria vesca L. The extracts with the highest anticoagulant activity were purified by multi-step extraction procedure and separated by gel permeation chromatography, giving rise to the macromolecular complexes. They were subsequently structurally characterized using colorimetric methods, FT-IR, GC-MS, and NMR (1H and 1H/13C HSQC), as polyphenolic-polysaccharide conjugates with the anticoagulant activity. The polysaccharide parts of the conjugates obtained by different extraction procedures were found to vary significantly. The most selective in their activity were the glycoconjugates extracted in UAE and MAE processes, i.e. arabinogalactan and pectin-like conjugates, respectively. In terms of their anticoagulant activity all of them were non-direct factor Xa inhibitors mediated by antithrombin.

The polyphenolic-polysaccharide complex of Agrimonia eupatoria L. as an indirect thrombin inhibitor - isolation and chemical characterization.

The polyphenolic-polysaccharide complex was isolated from the dried aerial parts of the medicinal plant Agrimonia eupatoria L. using a multi-step process involving the degreasing of the plant material by extraction with organic solvents, followed by extraction with hot alkali, neutralization, further separation with organic solvents and dialysis. The complex was homogeneous with a molecular weight of about 55 × 103 g/mol and consisted mainly of carbohydrates and polyphenols matrix, composed of lignin-related units, with the dominance of dimethoxyphenyl structures. The carbohydrate moiety consists mostly of arabinogalactan associated with highly esterified rhamnogalacturonan. In vitro anticoagulant studies revealed the ability of the A. eupatoria complex to inhibit plasma clot formation, mainly in the intrinsic pathway of the blood coagulation cascade. Further studies on the mechanisms of this anticoagulant activity revealed that the isolate was primarily an indirect inhibitor of thrombin, mediated by antithrombin or by heparin cofactor II. Such mechanism of action is characteristic for highly sulfated glycosaminoglycans.

Polyphenolic-polysaccharide conjugates of Sanguisorba officinalis L. with anticoagulant activity mediated mainly by heparin cofactor II.

A macromolecular complex has been isolated from the dried flowering parts of medicinal plant Sanguisorba officinalis L. (So) by multi-step extraction procedure, including that with extraction by organic solvents to degrease the plant material, then with hot alkali, followed by neutralization, partitioning with organic solvents and dialysis. The complex was purified by size-exclusion chromatography into five fractions labeled as So1-So5. Individual fractions differed in the chemical composition and molecular weight distribution patterns. In vitro anticoagulant activity tests showed in all fractions more or less important inhibition of plasma clots, however, So3 and So4 were the most active. The anticoagulant activity of So3 was even more significant than that of the unfractionated complex So. These S. officinalis conjugates were able to inhibit mainly the activity of thrombin when they were mediated by heparin cofactor II, but what was unexpected they were the non-direct inhibitors of factor Xa, mediated by antitrombin, where such mechanism of action is typical for a highly sulphated glycosaminoglycans.