Photographic Emulsions Research Articles

Sodium and potassium ferrocyanide derived Prussian blue pigment

Purpose This study aims to synthesize Prussian blue {FeIII4[FeII(CN)6]3} pigment by reacting ferric chloride with different ferrocyanides through the same procedure. The influence of the ferrocyanide used on resulting pigment properties is studied. Design/methodology/approach Prussian blue is commonly synthesized by direct or indirect methods, through iron salt and ferrocyanide/ferricyanide reactions. In this study, the direct, single-step process was pursued by dropwise addition of the ferrocyanide into ferric chloride (both as aqueous solutions). Two batches – (K-PB) and (Na-PB) – were prepared by using potassium ferrocyanide and sodium ferrocyanide, respectively. The development of pigment was confirmed by an identification test and characterized by spectroscopic techniques. Pigment properties were determined, and light fastness was observed for acrylic emulsion films incorporating dispersed pigment. Findings The two pigments differed mainly in elemental detection owing to the dissimilar ferrocyanide being used; IR spectroscopy where only (Na-PB) showed peaks indicating water molecules; and bleeding tendency where (K-PB) was water soluble whereas (Na-PB) was not. The pigment exhibited remarkable blue colour and good bleeding resistance in several solvents and showed no fading in 24 h of light exposure though oil absorption values were high. Originality/value This article is a comparative study of Prussian blue pigment properties obtained using different ferrocyanides. The dissimilarity in the extent of water solubility will influence potential applications as a colourant in paints and inks. K-PB would be advantageous in aqueous formulations to confer a blue colour without any dispersing aid but unfavourable in systems where other coats are water-based due to their bleeding tendency.

Polymer-modified cement-based coating containing organic-inorganic silicons modified polyacrylate emulsion: Performance and mechanisms

How to simply and effectively improve the mechanical properties and UV resistance of polymer-modified cement-based coatings is the key to expand its application field. In this study, a novel type of polyacrylate (M-PA) emulsion modified by polydimethylsiloxane (PDMS), colloidal nano-silica (CNS), and 3-Glycidyloxypropyltrimethoxysilane (KH-560) was prepared based on the response surface methodology (RSM) to achieve composition optimization. In addition, the effect of M-PA emulsion on the mechanical properties, impermeability, microstructure, and UV resistance was comprehensively studied. The research results demonstrated that the tensile strength and hydrophobicity of M-PA emulsion film were the best when the content of CNS, PDMS and KH560 was 16–17%, 6–7% and 0.075–0.12%. The reason can be attributed to the chemical combination of modifier and the formation of ‘Si-O-Si’ of three-dimensional network structure in M-PA emulsion. In comparison with a coating containing unmodified PA emulsion, the bond and tensile strength of M-PA modified samples were increased by 29% and 43%, respectively, while the water absorption was reduced by 28% due to the refinement of microstructure. As a result, the hydrophobic film of the modified coating was still intact after UV-aging for 1000 h.

Physicochemical and antimicrobial properties of soy protein isolate films incorporating high internal phase emulsion loaded with thymol

Oil-in-water (O/W) high internal phase (HIP) emulsion was prepared to investigate its effects on the physicochemical properties and antimicrobial properties of soy protein isolate (SPI)-based films. The particle size and migration degree of oil droplets in the SPI film-forming solution with HIP emulsion and the films were lower than those with conventional O/W emulsion or oil. The SPI-based emulsion films with HIP emulsion containing 30 % oil had the lowest water vapor permeability (1.15 × 10−10 g·m−1·s−1·Pa−1), glass transition temperature (40.93 °C) and tensile strength (4.47 MPa), and the highest transparency value (12.87) and elongation at break (160.83 %). The antimicrobial test of the SPI-based emulsion films loaded with thymol showed that the thymol encapsulation efficiency, sustained release effect, and growth inhibition effect on microbes were higher for the films with HIP emulsion than those for the films with O/W emulsion or oil.

Preparation of light‐responsive block copolymer modified cellulose nanocrystal@polydopamine particle and its application in fluorinated polyacrylate film

AbstractLight‐responsive cellulose nanocrystal@polydopamine (CNC@PDA) modified fluorinated polyacrylate was synthesized by Pickering emulsion polymerization with light‐responsive block copolymer modified CNC@PDA as stabilizer. The epoxy groups in poly(acrylic acid‐co‐acrylamide)‐b‐poly(glycidyl methacrylate)‐b‐poly(hexafluorobutyl acrylate‐co‐coumarin) amphiphilic triblock copolymer reacted with the hydroxyl and amino groups on the surface of CNC@PDA to form the modified CNC@PDA. The successful preparation of modified CNC@PDA was confirmed by means of FT‐IR, XRD, TG, UV–Vis, surface tension measurement, and X‐ray photoelectron spectroscopy (XPS) techniques. The results showed that the modified CNC@PDA had light‐responsive and amphiphilic properties, and could be used as stabilizer to form stable Pickering emulsion. And the influence of modified CNC@PDA dosage on emulsion polymerization and film performance was systematically studied. The latex particle size decreased initially with increasing modified CNC@PDA dosage, from 0.6 to 1.0 wt%, and then increased. The mechanical, self‐healing, and water–oil repellent properties of film were enhanced initially with increasing modified CNC@PDA dosage, from 0.6 to 1.0 wt%, and then declined. Atomic force microscope confirmed that the latex film had a rough surface. Moreover, the latex film comprising 1.0 wt% modified CNC@PDA presented not only high tensile strength (4.92 MPa), large elongation at break (657.70%), and superior oil/water repellency but also excellent self‐healing property.

Development of Multiple Crosslinked Polymers and Its Application in Synthetic-Based Drilling Fluids.

This study addresses the performance challenges of Synthetic-Based Drilling Fluids (SBDF) in deep wells and high-temperature environments by engineering a novel multiple hydrogen-bonded crosslinked polymer, MBAH/nano-SiO2. Synthesized using methyl methacrylate (MMA), butyl methacrylate (BMA), acrylic acid (AA), N-hydroxyethyl acrylamide (HEAA), and nano-silica (nano-SiO2), the polymer improved crosslinking density, thermal properties, particle size distribution, and colloidal stability. The development of a 'weak gel' structure in W/O emulsions improved rheology and electrical stability (ES), with ES values reaching up to 775 V after aging at 180 °C. Moreover, the polymer's amphiphilic structure and the synergistic effect of nano-SiO2 increased emulsion film thickness and strength, further augmenting stability. The high-temperature and high-pressure filtration loss of SBDF was considerably reduced to 7.6 mL, benefiting well wall stability and reservoir damage control. This study provides crucial insights into optimizing multiple hydrogen-bonded crosslinked strategies and polymers in SBDF applications.

Encapsulated phenolic compounds: clinical efficacy of a novel delivery method

AbstractEncapsulation is a drug or food ingredient loaded-delivery system that entraps active components, protecting them from decomposition/degradation throughout the processing and storage stages and facilitates their delivery to the target tissue/organ, improving their bioactivities. The application of this technology is expanding gradually from pharmaceuticals to the food industry, since dietary bioactive ingredients, including polyphenols, are susceptible to environmental and/or gastrointestinal conditions. Polyphenols are the largest group of plants' secondary metabolites, with a wide range of biological effects. Literature data have indicated their potential in the prevention of several disorders and pathologies, ranging from simpler allergic conditions to more complex metabolic syndrome and cardiovascular and neurodegenerative diseases. Despite the promising health effects in preclinical studies, the clinical use of dietary polyphenols is still very limited due to their low bioaccessibility and/or bioavailability. Encapsulation can be successfully employed in the development of polyphenol-based functional foods, which may improve their bioaccessibility and/or bioavailability. Moreover, encapsulation can also aid in the targeted delivery of polyphenols and may prevent any possible adverse events. For the encapsulation of bioactive ingredients, several techniques are applied such as emulsion phase separation, emulsification/internal gelation, film formation, spray drying, spray-bed-drying, fluid-bed coating, spray-chilling, spray-cooling, and melt injection. The present review aims to throw light on the existing literature highlighting the possibility and clinical benefits of encapsulated polyphenols in health and disease. However, the clinical data is still very scarce and randomized clinical trials are needed before any conclusion is drawn. Graphical abstract

On the nature of apparent transient sources on the National Geographic Society–Palomar Observatory Sky Survey glass copy plates

Abstract We examine critically recent claims for the presence of above-atmosphere optical transients in publicly available digitized scans of Schmidt telescope photographic plate material derived from the National Geographic Society–Palomar Observatory Sky Survey. We employ the publicly available SuperCOSMOS Sky Survey catalogues to examine statistically the morphology of the sources. We develop a simple, objective, and automated image classification scheme based on a random forest decision tree classifier. We find that the putative transients are likely to be spurious artefacts of the photographic emulsion. We suggest a possible cause of the appearance of these images as resulting from the copying procedure employed to disseminate glass copy survey atlas sets in the era before large-scale digitization programmes.

СУБПІКСЕЛЬНЕ СКАНУВАННЯ ДЛЯ АНАЛІЗУ ЗОБРАЖЕНЬ СПЕКТРА

Subject and Purpose. In this paper, an algorithm is developed to improve the spectrum image resolution in the atomic emission spectrum registration using multi-element detectors and taking multiple exposures with image shifting by a fractional part of a pixel. Methods and Methodology. Mathematical modeling techniques are employed in the coordinate representation dictated by the prior information. The modeling results are checked by experiment. Results. The importance of the resolution value of spectral image registration systems and its impact on the quality of the obtained results have been highlighted. The spectral informativeness of the regularly (matrix- or linearly) structured multi-element detectors has been evaluated against the irregular-structure sensors, such as photographic emulsions. As it has been found that the process of pixel size reduction is demanding, an alternative approach through subpixel image shifting has been proposed. Unlike the case of the corresponding instruments implemented as a rule in the frequency domain, here the relevant theoretical problem reduces to the over- determined system of linear equations. The proposed solution algorithm employs the least squares method having regard to the prior data specificity posed by the isolation of the spectral lines and a smooth flow of the background between them. The digital simulation results and the real experimental evidence from the atomic emission spectral analysis have been presented, illustrating the algorithm operation. The experimental research was carried out for one-dimensional spectrum images registered with linear charge-coupling photodetectors. The so gained resolution was twice the spatial resolution of the photodetector. Conclusions. It has been demonstrated that controlled image shifting not only improves the photometry accuracy but also significantly enhances the detector resolution. The general comparisons of the theory with the experiment have proved the feasibility of bringing the proposed methodology into atomic emission analysis.

Effects of oregano essential oil Pickering emulsion and ZnO nanoparticles on the properties and antibacterial activity of konjac glucomannan/carboxymethyl chitosan nanocomposite films.

Green and environmentally friendly natural bio-based food packaging films are increasingly favored by consumers. This study incorporated carboxylated-cellulose nanocrystal stabilized oregano essential oil (OEO) Pickering emulsion and ZnO nanoparticles (ZNPs) into konjac glucomannan (KGM)/carboxymethyl chitosan (CMCS) complexes to develop active food packaging films. The effects of OEO Pickering emulsion and ZNPs on the physical, structural, and antimicrobial activities of the nanocomposite films were evaluated. The OEO Pickering emulsion had a droplet size of 48.43 ± 3.56 μm and showed excellent dispersion and stability. Fourier transform infrared and X-ray diffraction analyses suggested that the interactions between the Pickering emulsion, ZNPs and KGM/CMCS matrix were mainly through hydrogen bonding. SEM observations confirmed that the Pickering emulsion and ZNPs were well incorporated into the KGM/CMCS matrix, forming tiny pores within the nanocomposite films. The incorporation of the OEO Pickering emulsion and/or ZNPs obviously increased the light and water vapor barrier ability, thermal stability, mechanical strength and antimicrobial properties of the KGM/CMCS nanocomposite film. Notably, KGM/CMCS/ZNPs/OEO Pickering emulsion films exhibited the highest barrier, and mechanical and antimicrobial activities due to the synergistic effect between the OEO Pickering emulsion and ZNPs. These results suggest that KGM/CMCS/ZNPs/OEO Pickering emulsion films can be utilized as novel active food packaging materials to extend the shelf life of packaged foods.

Polyvinyl alcohol films incorporated with clove essential oil emulsions stabilized by soy protein isolate-derived amyloid fibrils: Fabrication, characterization, and its application for active packaging

This study aimed to prepare a novel emulsion film with high stability, using soy protein-derived amyloid fibrils (SAFs) as an emulsifier incorporating clove essential oil (CEO) as the active component, and the polyvinyl alcohol (PVA) matrix to stabilize the system. The results demonstrated that SAFs can successfully stabilize CEO. Emulsion prepared by SAFS and CEO (SAC) exhibited a small droplet size and better dispersibility compared with SPI and CEO (SC) emulsion. According to FT-IR results, PVA addition increased the hydrogen bond interactions among emulsion film components, thus further reinforcing the protein matrix, increasing the tensile strength (TS) (41.18 MPa) and elongation at break (E) (121.62 %) of the films. The uniform appearance of SAC-PVA (SACP) emulsion films was confirmed by SEM images. Furthermore, SACP emulsion films show distinctive barrier properties, optical properties, and outstanding antioxidant properties. Finally, emulsion films exhibited excellent preservation of strawberries, resulting in an effective decline of the decay rate.

Super-resolution imaging for the detection of low-energy ion tracks in fine-grained nuclear emulsions

We propose a new wide-field imaging method that exploits the Localized Surface Plasmon Resonance phenomenon to produce super-resolution images with an optical microscope equipped with a custom design polarization analyzer module. In this paper we describe the method and apply it to the analysis of low-energy carbon ion tracks implanted in a nuclear emulsion film. The result is then compared with the measurements of the same tracks carried out at an electronic microscope. The images set side by side show their close similarity. The resolution achieved with the current microscope setup is estimated to be about 50 nm.

Properties of konjac glucomannan/curdlan-based emulsion films incorporating camellia oil and the preservation effect as coatings on ‘Kyoho’ grapes

The strategy of emulsion coating was used for grape preservation. Camellia oil (CO) was incorporated with KGM/curdlan (KC) to fabricate KC-CO emulsion systems. KC-CO emulsions were analyzed by droplet size distribution and confocal laser scanning microscopy (CLSM), and KC-CO films were investigated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), mechanical properties, dissolution, gas permeability, water contact angle (WCA). KC-CO coating was used for preservation of ‘Kyoho’ grapes. The results indicated that the addition of CO had a positive effect on KC system. CO could form a uniform emulsion with KC, and the droplets were evenly dispersed in the KC matrix. KC-CO films displayed a continuous microstructure, and elongation at break (EAB) was improved, while tensile strength decreased. The dissolution, water vapor permeability (WVP), and WCA were significantly enhanced, while the permeability of oxygen and carbon dioxide exhibited no advantage compared with KC film. KC-CO-10 possessed optimal properties and was selected as an emulsion coating for preservation. The results suggested that KC-CO-10 significantly maintained the appearance, total solid and acid content of ‘Kyoho’ grapes, and delayed the weight loss and firmness decrease. This study contributed to the understanding of polysaccharide-lipid emulsion system and the applications.

Fabrication of nanocomposite gelatin-based film by the pickering emulsion containing nanoparticles of chitin

The effect of different amounts of pickering emulsion on the physical, thermal, and structural properties of gelatin nanocomposite film containing chitin nanocrystals (NCs) was examined in the present study. Pickering emulsions were produced using chitin NCs with 0.7, 1, and 1.3% concentrations, and their characteristics were investigated. The physical and thermal stability and zeta potential of the emulsion containing 1.3% nanocrystals were higher than those of the other emulsions; therefore, it was chosen to prepare the films. Nanocomposite films were produced with 10, 20, and 30% of pickering emulsion, and their physical, thermal, and structural characteristics were studied. The differential scanning calorimetry (DSC) thermograph showed good thermal stability of emulsion films compared to pure gelatin film. Fourier transform infrared spectroscopy (FT-IR) results confirmed the excellent compatibility of nanoparticles with gelatin film. The barrier property of emulsion films was better than that of pure gelatin film. Therefore, about 10% emulsion containing 1.3% nanoparticles in nanocomposite films can create biodegradable biopolymers for food packaging.

Role of hydrodynamic conditions and type of foam stabilizer for antifoam efficiency

The effects of antifoam and surfactant concentration on the foamability of solutions of an anionic (SLES) and nonionic (Brij 35) surfactants and a series of polyvinyl alcohols with 88% and 98% degree of hydrolysis and molecular masses between 31 and 205 kDa, were studied. Three methods which differ in the way of air incorporation were used for foaming – Bartsch test, shake test and Ultra Turrax. Mixed silicone oil-silica particles antifoam was studied. The antifoam was introduced in the foaming solution as pre-dispersed in organic solvent or as antifoam-in-water emulsion. It was shown that the antifoam is very active in the fast foaming methods (Bartsch and shake tests) for the slow adsorbing polymers PVA and has no any activity in the slow foaming method (Ultra Turrax) for the fast adsorbing surfactants with electrostatic stabilization (SLES). The efficiency of pre-dispersed in organic solvent antifoam is much higher as compared to that of emulsified antifoam, due to the faster segregation of the silica particles and silicone oil in the emulsified antifoam. The antifoam efficiency increases with antifoam concentration and with lowering the surfactant concentration. In a given foaming method, the antifoam efficiency is the highest in PVA solutions with 98% DH, intermediate for PVA with 88% DH and Brij 35, and the lowest for SLES solutions. At a certain degree of hydrolysis, the molecular mass of PVA has no significant effect on the antifoam activity. Good correlation between the antifoam efficiency and the stability of the pseudo emulsion film formed between the antifoam globule and the bubble surface is established, showing that the electrostatic repulsion is more efficient to prevent the entering of the antifoam globules on the air-water interface, as compared to the steric repulsion.

GEOCHEMICAL VIEW ON “INOFFENSIVE” DEPLETED URANIUM

The interaction of alpha radiation from UO2 micro- and nanoparticles (uraninite) with the substance was visualized using alpha-autoradiography data on A-2 thick-layer nuclear photographic emulsions. The spherical area of action of alpha particles around UO2 micrograins, up to 100 microns in size, is a deeply transformed substance with a high density of radiation defects. The translation of these results on a living organism leads to the conclusion about the specific type of impact of micro- and nanoparticles of depleted uranium, in which prolonged internal irradiation in small doses of the whole organism is combined with catastrophically high doses of alpha radiation in local zones, near micro- and nanoparticles UO2.

Development and application of multifunctional films based on modified chitosan/gelatin polyelectrolyte complex for preservation and monitoring

Green and sustainable natural macromolecular-based multifunctional packaging has received widespread attention due to its excellent fresh-keeping effect and sensitive monitoring function. Herein, water-soluble modified chitosan (GCS) as the film substrate and emulsifier was synthesized first. Based on gelatin and GCS, a composite film (GF/GCS) and an emulsion film containing garlic essential oil (GF/GCSE2) were fabricated and compared. The interactions mainly included intermolecular hydrogen bonds and electrostatic interactions. The incorporation of GCS and the emulsion enhanced the hydrophobicity (water contact angle >100°) of films and also endowed the films with antioxidant activity and antibacterial activity (up to 100% for S. aureus and 97% for E. coli). Moreover, anthocyanins extracted from purple cabbage were added to the above two films as indicators to form pH-responsive smart labels GF/GCS/A and GF/GCSE/A. The gelatin/GCS polyelectrolyte complex improved the stability of anthocyanins in labels. Compared to commercial PE film, GF/GCS and GF/GCSE2 displayed better preservation effects on cherry tomatoes and fish. GF/GCSE2 exhibited the best preservation effect on cherry tomatoes, significantly reducing the decrease in total phenolic content and titratable acids. The integrated packaging composed of GF/GCS and GF/GCS/A could effectively prevent fish spoilage (TVB-N<15 mg/100 g) and sensitively reflected the freshness of fish during storage at 4 °C.

Beeswax: A review on the recent progress in the development of superhydrophobic films/coatings and their applications in fruits preservation.

Recently, the design and fabrication of bio-inspired superhydrophobic materials using natural lipid additives such as beeswax (BW) have aroused great attention in food packaging as they can minimize the transfer rate of water molecules and have effective moisture barriers. This review discusses the recent progress in the design and fabrication of BW-containing edible films/coatings (e.g., emulsion and blend films, bilayer materials, bionanocomposites, and antimicrobial materials) and their potential applications on the postharvest life and quality attributes of various fruits. Incorporation of BW into polysaccharides- and proteins-based emulsion films effectively improved their hydrophobicity, water vapor, and UV/visible light barrier properties, as well as the film tensile properties. The addition of nanoparticles to BW-based polymeric matrices often results in improved physico-mechanical properties. BW coatings have been also applied to prolong the shelf-life of various climacteric fruits, however, optimization of the wax concentration can be further investigated to develop targeted food storage systems.

Recent Advances in Lycopene for Food Preservation and Shelf-Life Extension.

In recent years, there has been increasing concern about the safety of additives used to extend the shelf-life of food products. As a result, lycopene, a natural phytochemical compound, has attracted attention, as it has been demonstrated to be a potential alternative to traditional artificial antioxidants, with significant health benefits when applied to food preservation. Based on this, this review introduces the specific forms of lycopene currently used as an antioxidant in foods, both in its naturally occurring forms in fruits and vegetables and in artificially added forms involving technologies such as composite coating, active film packaging, emulsion, and microcapsules. In addition, it also provides a comprehensive summary of the effects and progress of lycopene in the preservation of different types of food products, such as meat, seafood, oil, dairy products, fruits, and vegetables, in the last decade. At last, it also points out the limitations of lycopene, including its insolubility in water, dark color, and high sensitivity to heat or light, as well as the potential solutions to load lycopene on suitable carriers, such as combining lycopene with antimicrobial substances or other actives, in order to broaden its applications as an antioxidant in future foods.

Enhancement of a hybrid colorimetric film incorporating Origanum compactum essential oil as antibacterial and monitor chicken breast and shrimp freshness

Recently, intelligent packaging has combined several functions, including monitoring and preserving food freshness in real-time. This study was developed a hybrid film (active/ colorimetric) based on AM/CPC/9%SFW as a carrier of Origanum compactum essential oil (OC) in various concentrations (0%, 1%, 1.25%, and 1.5% v/v). The film's emulsions showed homogeneity regarding particle size, polydispersity index, and ζ -potential. Hybrid films' morphological, mechanical, water and light barrier, thermal, and antioxidant properties were enhanced with an increased OC. Interestingly, all films rapidly responded to pH/NH3 and reflected different colors. In the hybrid films, an inhibition effect against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria and OC (1.5%) film exhibited a large inhibition zone attained diameters of 37.33 and 15.67 mm, respectively, in the disc diffusion test. Outstanding, AM/CPC/9%SFW/1.5 %OC film displayed the ability to preserve and monitor chicken breast and shrimp freshness to 33 and 21 h, respectively, during storage at 25 °C.

Effect of droplet size on the film formation of O/W emulsion

PurposeThe purpose of this study is to reveal the underlying mechanism in film formation of oil-in-water (O/W) emulsion.Design/methodology/approachThis study focuses on the film forming characteristics of O/W emulsion between the surface of a steel ball and a glass disc coated with chromium. The lubricant film thicknesses of O/W emulsion with various mechanical stirring strength were discussed, which were observed by technique of relative optical interference intensity.FindingsThe authors directly observed the oil pool in the contact area, finding the size of oil pool was closely related to the film-forming ability of emulsion. Enrichment phenomenon occurs in oil pool, which was caused by phase inversion. Further investigations revealed that the emulsion is stable with strong stirring strength, resulting in a smaller oil pool size and worse film forming ability.Originality/valueWith the wide usage of O/W emulsion in both biological and industrial systems, the ability of emulsion film formation is considered as an important factor to evaluate the lubrication effectiveness.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-12-2022-0354/