Blend Films Research Articles

Influence of citronella essential oil and TiO2 nanoparticles on the optical, mechanical and thermal characteristics of chitosan/poly(vinyl alcohol) blended films and nanofibers

Influence of citronella essential oil and TiO2 nanoparticles on the optical, mechanical and thermal characteristics of chitosan/poly(vinyl alcohol) blended films and nanofibers

PREVENTION OF RODENT ATTACK ON TERTIARY PACKAGE AT STORAGE LEVEL

Packaging is the science, art and technology of enclosing or protecting products for distribution, storage, sale, and use. Theses packaging are done at three levels they are namely primary, secondary and tertiary. Tertiary packaging is a type of wrapping which protects the manufactured products. It is used to smooth the progress of the transport and safe handling of goods. The synthetic polymer is best suitable for packaging as they are having good strength properties. It is selected for packaging application based on their grade of suitability and recyclability towards product. The production of film for tertiary pack at storage level is mainly focused on availability and process capabilities. The problem mostly arises in the case of tertiary packaging sector where the goods are packed and stored at warehouse. The synthesis of film was carried out by blending linear low density polyethylene and essential oil as a plasticizer through solvent casting method. The synthesis is accomplished by formulating the elements certain percentage toproduce film suitable for packaging. Thereafter testing was carried out and found that elongation has improvedfor LLDPE blends at a rate of 65.6% than LLDPE. The tensile strength was found to be reduced in LLDPE blends with value of 1.60Mpa. The contact angle was measured and it was found that the LLDPE film produce hydrophobicity than LLDPE with an increase of 3%. The UV spectroscopy was also measured and it was found that LLDPE blend film gave a translucent effect. The rodent test was also carried out and LLDPE film tends to repel them. Thus the LLDPE blends are made suitable for tertiary package.

Development of n-Type Small-Molecule Acceptors for Low Dark Current Density and Fast Response Organic Photodetectors.

Suppressing the dark current density (Jd) while maintaining sufficient charge transport is important for improving the specific detectivity (D*) and dynamic characteristics of organic photodetectors (OPDs). In this study, we synthesized three novel small-molecule acceptors (SMAs) densely surrounded by insulating alkyl side chains to minimize the Jd in OPDs. Introducing trialkylated N-annulated perylene diimide as a terminal moiety to the alkylated π-conjugated core structure was highly efficient in suppressing Jd in the devices, resulting in an extremely low Jd of 4.60 × 10-11 A cm-2 and 10-100 times improved D* values in the devices. In addition, SMAs with a geometrically aligned backbone structure exhibited better intermolecular ordering in the blended films, resulting in 3-10 times as high responsivity (R) values in the OPDs. Outstanding OPD performances with a D* of 8.09 × 1012 Jones, -3 dB cutoff frequency of 205.2 kHz, and rising response time of 16 μs were achieved under a 530 nm illumination in photoconductive mode. Geometrically aligned core-terminal SMAs densely surrounded by insulating alkyl side chains are promising for improving the static and dynamic properties of OPDs.

Halogenated Nonfused Ring Electron Acceptor for Organic Solar Cells with a Record Efficiency of over 17.

Three nonfused ring electron acceptors (NFREAs), namely, 3TT-C2-F, 3TT-C2-Cl, and 3TT-C2, are purposefully designed and synthesized with the concept of halogenation. The incorporation of F or/and Cl atoms into the molecular structure (3TT-C2-F and 3TT-C2-Cl) enhances the π-π stacking, improves electron mobility, and regulates the nanofiber morphology of blend films, thus facilitating the exciton dissociation and charge transport. In particular, blend films based on D18:3TT-C2-F demonstrate a high charge mobility, an extended exciton diffusion distance, and a well-formed nanofiber network. These factors contribute to devices with a remarkable power conversion efficiency of 17.19%, surpassing that of 3TT-C2-Cl (16.17%) and 3TT-C2 (15.42%). To the best of knowledge, this represents the highest efficiency achieved in NFREA-based devices up to now. These results highlight the potential of halogenation in NFREAs as a promising approach to enhance the performance of organic solar cells.

Designing high‐performance nonfused ring electron acceptors via side‐chain engineering

AbstractThe side‐chain has a significant influence on the optical properties and aggregation behaviors of the organic small molecule acceptors, which becomes an important strategy to optimize the photovoltaic performance of organic solar cells. In this work, we designed and synthesized three brand‐new nonfused ring electron acceptors (NFREAs) OC4‐4Cl‐Ph, OC4‐4Cl‐Th, and OC4‐4Cl‐C8 with hexylbenzene, hexylthiophene, and octyl side chains on the π‐bridge units. Compared with OC4‐4Cl‐Ph and OC4‐4Cl‐Th, OC4‐4Cl‐C8 with linear alkyl side chain has more red‐shift absorption, which is conducive to obtaining higher short‐circuit current density. Additionally, the OC4‐4Cl‐C8 film exhibits a longer exciton diffusion distance, and the D18:OC4‐4Cl‐C8 blend film displays faster hole transfer, weaker bimolecular recombination, and more efficient exciton transport. Furthermore, The D18:OC4‐4Cl‐C8 blend films may effectively form interpenetrating networks that resemble nanofibrils, which can facilitate exciton dissociation and charge transport. Finally, OC4‐4Cl‐C8‐based devices can be created a marvellously power conversion efficiency (PCE) of 16.56%, which is much higher than OC4‐4Cl‐Ph (12.29%)‐ and OC4‐4Cl‐Th‐based (11.00%) ones, being the highest PCE among the NFREA based binary devices. All in all, we have validated that side‐chain engineering is an efficient way to achieve high‐performance NFREAs.

Effect of solvent and thermal annealing on D18/Y6 polymer solar cells

Organic solar cells (OSCs) as emerging generation solar cells are required to face climate and energy challenges. In this regard, OSCs based on the D18:Y6 active layer with a ratio of 1:1.6 with thermal and solvent annealing as a post-treatment were fabricated. The effect of different thermal annealing with chloroform on the active layer and the cell performance was studied. Optical, morphological and thermal analysis are executed to investigate the effect of thermal with solvent annealing on the D18:Y6 active layer. Photoluminescence (PL), transmission electron microscope (TEM) and atomic force microscope (AFM) reveal that D18:Y6 film treated at 55 °C with chloroform for 5.0 min had the lowest PL intensity, interpenetrating grain networking structures and more smoother surface leads to optimize photo-induced charge transfer and exciton dissociation in the active layer. D18: Y6 blend film annealed at 80 °C with chloroform for 5.0 min exhibits higher roughness of 17.81 nm than 11.60 nm for D18:Y6 blend film treated at 55 °C. As a result, the optimal performance of the fabricated conventional OSCs based on active layer treated at 55 °C with chloroform had short-current density (Jsc), open circuit voltage (Voc), fill factor (FF) and efficiency of 60 mA/cm2, 0.70V, 39.8% and 16.5%, respectively. This study indicates additional thermal annealing with chloroform as a post-treatment enhances the device performance of OSCs.Graphical abstractStudying the effect of solvent vapor annealing with thermal annealing of D18:Y6 layer aspost-treatment on the performance of organic solar cells.

Smart packaging films based on corn starch/polyvinyl alcohol containing nano SIM-1 for monitoring food freshness

There is at present an acute need for the construction of biopolymer-based smart packaging material that can be applied for the real-time visual monitoring of food freshness. Herein, a nano-sized substituted imidazolate material (SIM-1) with ammonia-sensitive and antibacterial ability was effectively manufactured and then anchored within corn starch/polyvinyl alcohol (CS/PVA) blend to construct biopolymeric smart active packaging material. The structure, physical and functional performances of CS/PVA-based films with different content of SIM-1 (0.5, 1.0 and 2.0 wt% on CS/PVA basis) were then explored in detail. Results revealed that the incorporated SIM-1 nanocrystals were equally anchored within the CS/PVA matrix owing to the establishment of potent hydrogen-bonding interactions, which produced an obvious improvement in the compatibility of CS/PVA blend film, as well as its mechanical strength, water/oxygen barrier and UV-screening performances. The constructed CS/PVA/SIM-1 blend films further demonstrated superior long-term color stability property, ammonia-sensitive and antibacterial functions. Furthermore, the CS/PVA/SIM-1 blend films were utilized for effectively monitoring the deterioration of shrimp via observable color alteration. The above findings suggested the potential applications of CS/PVA/SIM-1 blend films in smart active packaging.

Enhancing Photovoltaic Performance of Nonfused‐Ring Electron Acceptors via Asymmetric End‐Group Engineering and Noncovalently Conformational Locks

Comprehensive SummaryBy employing the asymmetric end‐group engineering, an asymmetric nonfused‐ring electron acceptor (NFREA) was designed and synthesized. Compared with the symmetric analogs (NoCA‐17 and NoCA‐18), NoCA‐19 possesses broader light absorption range, more coplanar π‐conjugated backbone, and appropriate crystallinity according to the experimental and theoretical results. The organic solar cells based on J52:NoCA‐19 exhibited a power conversion efficiency as high as 12.26%, which is much higher than those of J52:NoCA‐17 (9.50%) and J52:NoCA‐18 (11.77%), mainly due to more efficient exciton dissociation, better and balanced charge mobility, suppressed recombination loss, shorter charge extraction time, longer charge carrier lifetimes, and more favorable blend film morphology. These findings demonstrate the great potential of asymmetric end‐group engineering in exploring low‐cost and high‐performance NFREAs.

Porous antimicrobial crosslinked film of hydroxypropyl methylcellulose/carboxymethyl starch incorporating gallic acid for wound dressing application

Because of weak mechanical qualities and low degree of swelling of hydroxypropyl methylcellulose/carboxymethyl starch (HP/CMS) blended films for wound dressing application, this work prepared a unique antimicrobial crosslinked film utilizing succinic acid (SA) as a non-toxic crosslinker and gallic acid (GAL) as an antibacterial agent. It was observed that the infrared-shifted peak position of OH stretching and bending in HP/CMS/SA/GAL films was caused by hydrogen bond formation among HP, CMS and GAL components. The antimicrobial crosslinked films considerably enhanced their mechanical properties and swelling degree. After adding SA and GAL, the films retained their porosity structure as observed by scanning electron images. Moreover, GAL-loaded HP/CMS/SA films could inhibit Staphylococcus aureus and Escherichia coli growth, showing their wound dressing potential. Crystallinity percentage, water vapor transmission rate, gel fraction, water solubility, water uptake and cytotoxicity were also investigated.

Petal-like Patterning of Polylactide/Poly (Butylene Succinate) Thin Films Induced by Phase Separation.

Biodegradable plastics are attracting attention as a solution to the problems caused by plastic waste. Among biodegradable plastics, polylactide (PLA) and poly (butylene succinate) (PBS) are particularly noteworthy because of their excellent biodegradability. However, the drawbacks of their mechanical properties prompts the need to compound them to achieve the desired strength. The characteristics of the interface of the composite material determine the realization of its final performance. The study of the interface and microstructure of composites is essential for the development of products from degradable polymers. The morphology evolution and microcrystal structure of spin-casted fully biodegradable (PLA/PBS) blend films were investigated using atomic force microscopy (AFM)-based nanomechanical mapping. Results show that intact blend films present an obvious phase separation, where the PBS phase is uniformly dispersed in the PLA phase in the form of pores. Furthermore, the size and number of the PBS phase have a power exponential relationship and linear relationship with PBS loading, respectively. Intriguingly, after annealing at 80 °C for 30 min, the PLA phase formed an orderly petal-like microcrystalline structure centered on the PBS phase. Moreover, the microcrystalline morphology changed from a "daisy type" to a "sunflower type" with the increased size of the PBS phase. Since the size of the PBS phase is controllable, a new method for preparing microscopic patterns using fully biodegradable polymers is proposed.

Preparation of bioplastic film from chitosan and mango (Mangifera Indica L. Anacardiaceae) kernel starch by casting method

The accumulation of plastics in landfills and oceans has encouraged the development of biodegradable plastic products from renewable sources. Natural polymers are excellent candidates that need further modification of their functional and structural properties comparable to conventional plastics. This study aims to fabricate and optimize the formulation of bioplastic films from chitosan and mango kernel starch with glycerol as a plasticizer using response surface methodology (RSM). The chitosan-to-starch mass ratio (1:0.17 to 1:5.83) and glycerol concentration per gram of dry polymer (15.86% to 44.14%) were assigned as the independent variables to design an empirical model that describes the films’ elastic modulus as the sole response. The results yielded an optimal formulation of 1:0.17 chitosan-to-starch mass ratio (2% weight by volume chitosan solution blend) with 15.86% glycerol (per gram of dry chitosan and starch). Reproduction of the optimized film was carried out to validate the empirical model. Characterization of the films’ mechanical and barrier properties, surface morphology, and biodegradability were also investigated in this work. The results suggest that the functional properties of the bioplastic film surpass other chitosan-based bioplastic film blends and can be developed further to become a more sustainable alternative to conventional plastic packaging products.

Enhanced mechanical property and water solubility of polyvinyl alcohol film via constructing hydrogen-bond network by adding carboxymethyl chitosan

The slight solubility of polyvinyl alcohol (PVA)/chitosan (CS) blends in water is an unavoidable drawback, which severely limits their applications in controlled drug-release and recycling. In the present work, carboxymethyl chitosan (CMCS) which has a good solubility in a wide PH range was used to modify the mechanical performance and water solubility of PVA-based blends. The results indicated that the PVA/CMCS blends were soluble in an aqueous medium at about PH = 7 and they also demonstrated better thermo-mechanical properties when compared with pure PVA. The PVA/CMCS blend film was compatible at a mid-low percentage of CMCS (i.e., 30% and 50%). The addition of CMCS effectively improved the mechanical strength and glass transition temperature of PVA by constructing intermolecular hydrogen bonds. Moreover, PVA/CMCS blends exhibited excellent solubility in neutral water, which demonstrate promising applications in the coating film industry.

Ultrafast Exciton Dissociation in Block Copolymer toward Efficient Single Material Organic Solar Cells

AbstractThe study reports for the first time on the ultrafast dynamics of charge transfer (CT) and exciton dissociation in block copolymer PBDB‐T‐b‐PTY6‐based state‐of‐the‐art single‐material organic solar cells (SMOSCs). From the transient absorption spectroscopy of the dilute PBDB‐T‐b‐PTY6 in the insulating polystyrene, exciton dissociation and hole transfer (HT) processes at the intramolecular interface of covalent linkage between the donor and acceptor segment are achieved. In comparison to the charge generation in blend PBDB‐T:PTY6 films, it is found that the HT rate in the isolated block copolymer chain via the intramolecular channel is approximately an order of magnitude higher than that via the intermolecular channel. Much faster exciton dissociation in the dilute PBDB‐T‐b‐PTY6 film than in the blend film from electro‐absorption and polaron‐absorption signals is also verified. The intrachain chemical interface in the block copolymer is thus more conducive to the HT path than the traditional interface in the bulk heterojunction. Moreover, though the PBDB‐T‐b‐PTY6 film has weak molecular ordering, its overall CT efficiency is comparable to that of the PBDB‐T:PTY6 film. These findings portend that further molecular design with optimized ordering toward fast intramolecular exciton dissociation may contribute to SMOSCs with higher power conversion efficiency.

Central Core Substitutions and Film-Formation Process Optimization Enable Approaching 19% Efficiency All-Polymer Solar Cells.

Molecular interactions and film-formation processes greatly impact the blend film morphology and device performances of all-polymer solar cells (all-PSCs). Molecular structure, such as the central cores of polymer acceptors, would significantly influence this process. Herein, the central core substitutions of polymer acceptors are adjusted and three quinoxaline (Qx)-fused-core-based materials, PQx1, PQx2, and PQx3 are synthesized. The molecular aggregation ability and intermolecular interaction are systematically regulated, which subsequently influence the film-formation process and determine the resulting blend film morphology. As a result, PQx3, with favorable aggregation ability and moderate interaction with polymer donor PM6, achieves efficient all-PSCs with a high power conversion efficiency (PCE) of 17.60%, which could be further improved to 18.06% after carefully optimizing device annealing and interface layer. This impressive PCE is one of the highest values for binary all-PSCs based on the classical polymer donor PM6. PYF-T-o is also involved in promoting light utilization, and the resulting ternary device shows an impressive PCE of 18.82%. In addition, PM6:PQx3-based devices exhibit high film-thickness tolerance, superior stability, and considerable potential for large-scale devices (16.23% in 1 cm2 device). These results highlight the importance of structure optimization of polymer acceptors and film-formation process control for obtaining efficient and stable all-PSCs.

Studies on Polystyrene/Polymethyl methacrylate Thin-Films: Structural and optical Properties

The thin film blends such as Polystyrene (PS) and Polymethyle Mythcrylate (PMMA) were prepared by dip coating technique. Pure and blended forms of thin films are to be characterized in the context of FTIR and XRD methods for micro structural analysis. AC conduction properties of polymers in the frequency range 10 kHz to 10 MHz at various temperatures (303–343 K) are reported and studies suggest that electron hopping is responsible for conduction. The activation energies associated with these thin films and optical properties are also studied.

Functional properties of taro starch reinforced polysaccharide based films for active packaging

The current study involves the fabrication of polysaccharide-based films containing Chitosan (CS) -Pullulan (PL) and Taro starch (TS), all derived from conventional sources. The extraction of starch from Taro (Colocasia esculenta) tubers was carried out by employing the wet-milling process in the laboratory. The main study was aimed at studying the influence of added TS into the CS-PL matrix through various characterization techniques such as mechanical, structural, spectroscopic, thermal, morphological and biological studies. The added TS was found to enhance the tensile strength as well as the crystallinity of the chitosan/pullulan (CP) blend films. The blend films showed a decline in the opacity values with the addition of TS. The effective interaction between the blended components indicated stronger intermolecular hydrogen bonding between them which was confirmed through FTIR and DSC studies. The thermal analysis depicted that the TS incorporated blend films degraded at a slightly higher temperature than the control film. The developed films were found to be hydrophobic in nature, with increasing hydrophobicity with increase in concentration of TS. The fabricated films were found to be biologically active i.e., antimicrobial and antioxidant, which is due to the presence of certain active compounds present in the taro tubers. These outcomes suggest that these films can be harnessed as active packaging materials in the food industry.

High-strength, water-resistant polyvinyl alcohol films reinforced with regenerated cellulose fibers for food packaging

Polyvinyl alcohol (PVA) film, a promising biodegradable packaging film material, shows low water resistance and mechanical properties, which hinder its application in the packaging field, particularly in humid or aqueous environments. Herein, PVA/regenerated cellulose fibers (RC) blend films (PVA/RC films) were fabricated by a simple controllable regeneration of cellulose fibers in an aqueous solution of PVA. The potentiation formed by the uniformly distributed RC in PVA/RC films and the competitive advantage of hydrogen bond (N···H-O) formation between urea and PVA afforded superior water resistance and mechanical characteristics to PVA/RC films. In particular, PVA/RC films displayed good tensile strength and elongation at break under dry and humid conditions (75.97 and 35.37 MPa; 281.17% and 624.83%, respectively). The shelf life of fresh strawberries packed in these blend films was extended by an additional 4 days. The present study revealed a simple and economical approach to manufacture PVA-based packaging film materials for use in humid and aqueous environments.

Influence of the Main Blown Film Extrusion Process Parameters on the Mechanical Properties of a High-Density Polyethylene Hexene Copolymer and Linear Low-Density Polyethylene Butene Copolymer Blend Used for Plastic Bags

Polyethylene plastic bags manufactured via blown film extrusion have different quality specifications depending on their intended use. It is known that the mechanical properties of a film depend on the process parameters established, but little is known concerning how they affect one another, even more so due to the variety of polyethylene materials and processing techniques. This study focuses on establishing a proper correspondence of important mechanical properties like the dart impact, tensile strength at break, and elongation at break with commonly used process parameters like the blow-up ratio, take-up ratio, thickness reduction, and neck height, for a high-density polyethylene hexene copolymer and a linear low-density polyethylene butene copolymer blend film. Because this polyethylene mixture is an anisotropic material, interesting R2 values equal to or higher than 0.90 were found: a BUR with elongation at break and tensile strength at break in the MD and TD, a TUR with elongation at break in the MD and tensile strength at break in the MD and TD, and a TR with elongation at break and tensile strength at break in the MD. Also, a relationship between the dart impact and both the neck height and thickness were found.

Exploring the Influence of P3HT on PTCA Crystallization and Phase Behavior in Thin Films.

The thermal properties and alignment of crystallinity of materials in thin films play crucial roles in the performance and reliability of various devices, especially in the fields of electronics, materials science, and engineering. The slight variations in the molecular packing of the active layer can make considerable differences in the optical and thermal properties. Herein, we aim to investigate the tuning of the physical properties of a blended thin film of n-type small organic molecules of perylene-3,4,9,10-tetracarboxylic acid (PTCA-SMs) with the mixing of the p-type polymer poly(3-hexylthiophene) (P3HT). The resulting thin films exhibit an enhanced surface crystallinity compared to the pristine material, leading to the formation of long crystallites, and these crystallites are thermally stable in the solid state, as confirmed by X-ray diffraction (XRD), atomic force microscopy (AFM), and thermal analysis using variable-temperature spectroscopic ellipsometry (VTSE) and differential scanning calorimetry (DSC). We believe that the crystalline structure of the obtained P3HT/PTCA-SMs blends is a combination of edge-on and face-on orientations, which enable the potential use of this material as an active layer in organic electronics.

Plant leaf mucilage/carrageenan/Eudragit® NE30D blended films: Optimization, characterization, and pharmaceutical application

Mucilage of C. pareira leaves was utilized, being manufactured for use in pharmaceutical products. Carrageenan and Eudragit® NE30D were used to combined. Glycerin was used as a plasticizer at a concentration of 20 % w/w based on the amount of polymer used. Computer software optimized its characteristics, including tensile properties, moisture uptake, and erosion; the optimal formulation was 1.4:1.2:2.8. The percentages of optimization error ranged from 8.48 to 13.80 %. Propranolol HCl was mixed to an optimal formulation. The film layer was tight, homogeneous, and smooth, with no holes. DSC thermogram showed no interaction peaks at 101.33 °C and 170.50 °C. Propranolol HCl concentration in the film ranged from 2.18 to 2.20 mg/cm2. Propranolol HCl was quickly released from the film. The kinetic model for the release profile was first-order kinetic. Although propranolol HCl had a high-release profile, its skin permeation was limited. The permeation lag time, Jss, and Kp were 1.60–2.65 h, 0.0182–0.0338 μg/cm2/h, and 9.10–15.35 cm/h, respectively. A significant amount of propranolol HCl residue was found on the skin's surface. Glycerin appeared to influence propranolol HCl permeability. Therefore, the plant leaf mucilage/carrageenan/Eudragit® NE30D blended film can be utilized in pharmaceutical applications to control drug release from its film layer.