Blend Films Research Articles

Gallic acid crosslinked peanut protein‐corn starch composite edible films produced at alkaline pH with ultrasound application

AbstractCorn starch and peanut protein blend films were prepared with and without gallic acid addition (0.25%, w/v) at pH 7, 9, and 11 by casting. The ultrasound (160 W, 20 kHz, 10 min) treatment was applied to the film‐forming solutions. This study aimed to develop biopolymer‐based films with gallic acid and to determine the interactions of components at different pHs and with ultrasound. The barrier, optical, mechanical, and thermal properties of films were examined. Moreover, structural characterization of films was conducted by Fourier transform infrared (FTIR), x‐ray diffraction, and trinitro benzenesulfonic acid assay to enlighten the crosslinking interactions of gallic acid with biopolymers at different pHs. At neutral pH, gallic acid behaved as plasticizer. By acting as a crosslinker at pH 9, gallic acid provided the lowest moisture content, darker and more opaque appearance, enhanced barrier performance and thermal stability. The crosslinking degrees of gallic acid‐enriched films were 49.1% (pH 7), 77% (pH 9), and 67.4% (pH 11). Additionally, gallic acid increased antioxidant capacity. The ultrasonication adversely affected the film properties by breaking bonds in the film structure. Peanut protein‐corn starch‐gallic acid films under mild alkaline conditions exhibited outstanding thermal stability, mechanical durability, light, and water barrier characteristics, making them appropriate for sustainable food packaging applications.

Manipulating electron linking units and side chains for high-performance all-polymer photodetectors with stability over 5000 h

All-polymer photovoltaic devices have attracted extensive attention for their promising applications in various flexible devices. Although abundant polymer donors with superior properties are developed, new polymer acceptors are urgently required to optimize or update the performances of the devices. Herein, three novel polymer acceptors, namely PY-DTT, PY-DTP-C, and PY-DTP-Ph, based on dithienothiophene (DTT) and dithienopyrrole (DTP) with alkyl and aryl side chains as the linking units respectively are synthesized and employed in the all-polymer photodetectors (all-PPDs). The PY-DTP-Ph shows broader absorption, stronger intermolecular interaction, and more coplanar molecular conformation compared with the other two acceptors. Blending with donor PM6, the PY-DTP-Ph based all-PPDs exhibit maximum responsivity of 292.1 mA W−1 and specific detectivity of 5.4 × 1013 cm Hz1/2 W−1 at a bias of −0.1 V. Furthermore, the device achieves fast response speed (τr/τf = 1.2/21.8 μs) and a large linear dynamic range of 105.0 dB. Intriguingly, the photodetectors present extraordinary air stability for 5000 h, attributing to the ideal miscibility and morphology of the blend films. These results demonstrate close relationships between the electron linking units, side chains and the basic properties of polymer acceptors, which in turn affects the performances of the photodetector devices.

Dual Stimuli-Responsive [2]Rotaxanes with Tunable Vibration-Induced Emission and Switchable Circularly Polarized Luminescence.

Aiming at the construction of novel stimuli-responsive fluorescent system with precisely tunable emissions, the typical 9,14-diphenyl-9,14-dihydrodibenzo[a, c]phenazine (DPAC) luminogen with attractive vibration-induced emission (VIE) behavior has been introduced into [2]rotaxane as a stopper. Taking advantage of their unique dual stimuli-responsiveness towards solvent and anion, the resultant [2]rotaxanes reveal both tunable VIE and switchable circularly polarized luminescence (CPL). Attributed to the formation of mechanical bonds, DPAC-functionalized [2]rotaxanes display interesting VIE behaviors including white-light emission upon the addition of viscous solvent, as evaluated in detail by femtosecond transient absorption (TA) spectra. In addition, ascribed to the regulation of chirality information transmission through anion-induced motions of chiral wheel, the resolved chiral [2]rotaxanes reveal unique switchable CPL upon the addition of anion, leading to significant increase in the dissymmetry factors (glum ) values with excellent reversibility. Interestingly, upon doping the chiral [2]rotaxanes in stretchable polymer, the blend films reveal remarkable emission change from white light to light blue with significant 6.5-fold increase in glum values up to -0.035 under external tensile stresses. This work provides not only a new design strategy for developing molecular systems with fluorescent tunability but also a novel platform for the construction of smart chiral luminescent materials for practical use.

Dual Stimuli‐Responsive [2]Rotaxanes with Tunable Vibration‐Induced Emission and Switchable Circularly Polarized Luminescence

AbstractAiming at the construction of novel stimuli‐responsive fluorescent system with precisely tunable emissions, the typical 9,14‐diphenyl‐9,14‐dihydrodibenzo[a, c]phenazine (DPAC) luminogen with attractive vibration‐induced emission (VIE) behavior has been introduced into [2]rotaxane as a stopper. Taking advantage of their unique dual stimuli‐responsiveness towards solvent and anion, the resultant [2]rotaxanes reveal both tunable VIE and switchable circularly polarized luminescence (CPL). Attributed to the formation of mechanical bonds, DPAC‐functionalized [2]rotaxanes display interesting VIE behaviors including white‐light emission upon the addition of viscous solvent, as evaluated in detail by femtosecond transient absorption (TA) spectra. In addition, ascribed to the regulation of chirality information transmission through anion‐induced motions of chiral wheel, the resolved chiral [2]rotaxanes reveal unique switchable CPL upon the addition of anion, leading to significant increase in the dissymmetry factors (glum) values with excellent reversibility. Interestingly, upon doping the chiral [2]rotaxanes in stretchable polymer, the blend films reveal remarkable emission change from white light to light blue with significant 6.5‐fold increase in glum values up to −0.035 under external tensile stresses. This work provides not only a new design strategy for developing molecular systems with fluorescent tunability but also a novel platform for the construction of smart chiral luminescent materials for practical use.

Charge photogeneration dynamics in non-fullerene polymer solar cells with fluorinated and non-fluorinated acceptors.

In this work, charge photogeneration and recombination processes of PM6:IDIC-4F and PM6:IDIC blend films were investigated by the steady-state and time-resolved spectroscopies, as well as the time-dependent density functional theory calculations. The peaks in absorption and photoluminescence (PL) spectra of IDIC and IDIC-4F solutions were assigned by combining the experiment and the simulation of UV-vis absorption and PL spectra. For neat acceptor films, the exciton diffusion length of neat IDIC and IDIC-4F films was estimated as ∼28.9 and ∼19.9nm, respectively. For PM6-based blend films, we find that the fluorine substitution engineering on the IDIC acceptor material can increase the phase separate size of acceptor material in blend films, resulting in the reduction of dissociation efficiencies of acceptor excitons. In addition, we find that the charge recombination in PM6:IDIC-4F is dominated by bimolecular recombination, in comparison to geminate type carrier recombination in PM6:IDIC blend films. In addition, we find that thermal annealing treatment has a weak influence on carrier recombination but slightly reduces the exciton dissociation efficiency of acceptor in PM6:IDIC blend films, leading to a slightly reduced power conversion efficiency of PM6:IDIC solar cells. These results may shed light on the design of high-performance semiconductor molecules for application in solar cells.

Chitosan silver nanoparticle inspired seaweed (Gracilaria crassa) biodegradable films for seafood packaging

As an alternative to conventional plastic packaging, the concept of developing blend films with bio-based materials seems to be an environmentally friendly approach. In the present study, blend films were prepared using ethanolic extract of Gracilaria crassa (GCE) with chitosan (CS) and silver nanoparticles (AgNPs). The developed films were evaluated based on the physical, mechanical, structural, barrier and antioxidant indices. The films were slightly yellowish in color (b* ranges 39.69–53.08) and smooth textured. The FTIR spectra confirmed the intermolecular interaction between film components and the combination of CS and GCE occurred by means of -OH groups and hydrophobic interaction due to the cross-linking effect of the plasticizer (glycerol). The antioxidant properties of the films were investigated via DPPH assay and total phenolic contents showed significant improvement (p < 0.05) upon incorporation of GCE. Similar observations were made for tensile parameter (37.29 ± 1.22–38.39 ± 1.09) compared to the control (29.71 ± 1.66). The thermal pattern of blended films showed greater stability with Tg of 112.6 °C. The formulated films significantly extended the shelf-life of shrimp nuggets in refrigerated storage (4 °C) up to 9 days. The study reveals that the incorporation of GCE/AgNPs with chitosan films can be an active packaging system in the field of sustainable food packaging technology.

Effect of Antihydrolysis Agents on the Structure and Properties of PBAT/PGA Blend Films under Artificial Accelerated Weathering

Effect of Antihydrolysis Agents on the Structure and Properties of PBAT/PGA Blend Films under Artificial Accelerated Weathering

Physical and biological characteristics of eco‐friendly films added with Cinnamomum zeylanicum extract for packaging materials

SummaryThe effects of Cinnamomum zeylanicum extract (CZE) at different rations (0%, 1%, 3% and 5%) on gelatin (GL)–polyvinyl alcohol (PVA) blend films were evaluated in relation to the structural, tensile strength, physical, antimicrobial and antioxidant properties of the films in this study. The results showed that water barriers of the film samples decreased, but the UV‐blocking property increased and became opaque at the highest GLPVA5 film. The tensile strengths of GLPVA, GLPVA1, GLPVA3 and GLPVA5 films were 1.21, 1.78, 1.62 and 1.95 MPa, respectively. The antimicrobial effect of these films was determined against Escherichia coli, Enterococcus faecalis, Salmonella typhimurium and Bacillus cereus according to the parallel stick method. Antioxidant properties of cinnamon extract were investigated using 2,2‐diphenyl‐1‐picryl‐hydrazil (DPPH) methods. The % inhibition of DPPH was found to be 82.00. No antibacterial effect was detected for B.cereus and E. faecalis at 0%, 1%, 3% and 5%. While no activity was observed in 0%, 1% and 3% cinnamon, 7.5 and 3.0 mm zones were detected in S. typhimirium and E. coli, respectively, in 5% cinnamon. The results suggest that the film samples could be used in a potential packaging with antioxidant and antibacterial properties.

Visualization of Nanocrystallites in Organic Semiconducting Blends Using Cryo-Electron Microscopy.

The efficiency of an organic solar cell is highly dependent on the complex, interpenetrating morphology, and molecular order within the composite phases of the bulk heterojunction (BHJ) blend. Both these microstructural aspects are strongly influenced by the processing conditions and chemical design of donor/acceptor materials. To establish improved structure-function relationships, it is vital to visualize the local microstructural order to provide specific local information about donor/acceptor interfaces and crystalline texture in BHJ blend films. The visualization of nanocrystallites, however, is difficult due to the complex semi-crystalline structure with few characterization techniques capable of visualizing the molecular ordering of soft materials at the nanoscale. Here, it is demonstrated how cryo-electron microscopy can be utilized to visualize local nanoscale order. This method is used to understand the distribution/orientation of crystallites in a BHJ blend. Long-range (>300nm) texturing of IEICO-4F crystallites oriented in an edge-on fashion is observed, which has not previously been observed for spin-coated materials. This approach provides a wealth of quantitative information about the texture and size of nanocrystallites, which can be utilized to understand charge generation and transport in organic film. This study guides tailoring the material design and processing conditions for high-performance organic optoelectronic devices.

Fabrication of antibacterial poly (L-lactic acid)/tea polyphenol blend films via reactive blending using SG copolymer

Poly (L-lactic acid) (PLLA) composite materials with both excellent antibacterial properties and mechanical properties are highly desirable for both food packaging and biomedical applications. However, a facile method to prepare transparent PLLA composite films with both excellent antibacterial and mechanical properties is still lacking. In this work, blend films based on PLLA, tea polyphenols (TP) and poly (styrene-co-glycidyl methacrylate) (SG) copolymers (PLLA/TP/SG) were prepared by melt blending using twin screw extruder. The blend films showed high transparency with a brownish color originated from tea polyphenols. Both SEM and DSC analyses confirmed that the blends are thermodynamically compatible. GPC and mechanical assessments demonstrated that the PLLA/TP binary blends exhibit reduced molecular weight and compromised mechanical properties, compared to neat PLLA. However, incorporating SG copolymer resulted in increased molecular weight and improved mechanical properties for the PLLA/TP/SG blends. The FT-IR spectra exhibited a shift to lower wavenumber for the absorption peak associated with the benzene ring on TPs after blending with PLLA and SG, indicating the occurrence of transesterification between PLLA and TP. Plate coating studies revealed that the PLLA/TP/SG blends with TP incorporation at 5 wt% exhibited a bacteriostatic rate of 99.99 % against Staphylococcus aureus and Escherichia coli. Overall, our study reveals that the PLLA/TP/SG blend films exhibit excellent antibacterial properties coupled with good mechanical properties, rendering them a promising candidate for antibacterial packaging materials.

Unveiling the Strain‐induced Microstructural Evolution and Morphology‐Stretchability Correlations of Intrinsically Stretchable Organic Photovoltaic Films

AbstractThe progress of stretchable and wearable photovoltaics relies heavily on intrinsically stretchable active layer films. Nevertheless, there is a paucity of research clarifying the connections between their microstructure, performance, and their adaptation to large strain in polymer electronic films. The current study utilizes multiple synchrotron X‐ray scattering methods to collectively examine the correlations between morphology and stretchability, as well as the microstructural evolution induced by stretching in three sample cases of highly stretchable ternary blend films. These blends contain over 30% by weight of a polymer elastomer, such as styrene‐ethylene‐butylene‐styrene block copolymer, integrated into the high‐performance polymer:nonfullerene small molecule mixture. Specifically, the real‐time microstructural changes of these durable organic photovoltaic films with elastomers are monitored when subjected to tensile stretching through in situ synchrotron X‐ray scattering. The experiments demonstrate that polymeric elastomers can effectively lower the degree of crystallinity in films and deform the crystallites of semiconductor molecules. The elastomeric component aids in stress dispersion during stretching, thereby improving the microstructural durability of blend films. This study provides new recommendations for advancing stretchable organic optoelectronic devices.

Fluoride releasing in polymer blends of poly(ethylene oxide) and poly(methyl methacrylate).

Introduction: Polymethyl methacrylate is a polymer commonly used in clinical dentistry, including denture bases, occlusal splints and orthodontic retainers. Methods: To augment the polymethyl methacrylate-based dental appliances in counteracting dental caries, we designed a polymer blend film composed of polymethyl methacrylate and polyethylene oxide by solution casting and added sodium fluoride. Results: Polyethylene oxide facilitated the dispersion of sodium fluoride, decreased the surface average roughness, and positively influenced the hydrophilicity of the films. The blend film made of polymethyl methacrylate, polyethylene oxide and NaF with a mass ratio of 10: 1: 0.3 showed sustained release of fluoride ions and acceptable cytotoxicity. Antibacterial activity of all the films to Streptococcus mutans was negligible. Discussion: This study demonstrated that the polymer blends of polyethylene oxide and polymethyl methacrylate could realize the relatively steady release of fluoride ions with high biocompatibility. This strategy has promising potential to endow dental appliances with anti-cariogenicity.

Wide‐Bandgap Polymers with a C(sp3)─F Polyfluoride Backbone Enable High‐Efficient Ternary Organic Solar Cells

AbstractFluorination strategy is demonstrated to be a successful approach for optimizing the electron distribution and morphology of organic photovoltaic materials. The previous works focus on introducing only a few C(sp2)─F bonds into conjugated backbone or C(sp3)─F bonds into sidechains. Herein, a new strategy by introducing C(sp3)─F polyfluoride unit into the backbone is proposed, wherein the fluorine atoms are not involved into the conjugation but can promote the intermolecular interaction between backbones. Two wide‐bandgap fluoropolymers are prepared and employed as the third component for ternary organic solar cells. As expected, even if there are six fluorine atoms in a single repeat unit, the relevant fluoropolymers possess complementary absorption and aligned energy levels. More importantly, the polyfluoride backbone affords adequate non‐covalent interactions, consequently enhancing the polymer aggregation and packing order, which is verified by a fibril‐like morphology in the blend film with the host polymer PM6 and only 10 wt.% fluoropolymer. In addition, the decreased surface energy caused by polyfluoride unit is beneficial for the improvement of domain purity and the formation of nanoscale phase separation between donor and acceptor materials. As a result, the fluoropolymer‐assisted ternary device displays a higher efficiency of 18.74% compared with the binary device (17.39%).

A Three-Dimensional Non-Fullerene Acceptor with Contorted Hexabenzocoronene and Perylenediimide for Organic Solar Cells.

Although fullerene derivatives such as [6,6]-phenyl-C61/C71-butyric acid methyl ester (PC61BM/PC71BM) have dominated the the photoactive acceptor materials in bulk heterojunction organic solar cells (OSCs) for decades, they have several drawbacks such as weak absorption, limited structural tunability, prone to aggregation, and high costs of production. Constructing non-fullerene small molecules with three-dimensional (3D) molecular geometry is one of the strategies to replace fullerenes in OSCs. In this study, a 3D molecule, contorted hexa-cata-hexabenzocoronene tetra perylenediimide (HBC-4-PDI), was designed and synthesized. HBC-4-PDI shows a wide and strong light absorption in the whole UV-vis region as well as suitable energy levels as an acceptor for OSCs. More importantly, the 3D construction effectively reduced the self-aggregation of c-HBC, leading to an appropriate scale phase separation of the blend film morphology in OSCs. A preliminary power conversion efficiency of 2.70 % with a champion open-circuit voltage of 1.06 V was obtained in OSCs with HBC-4-PDI as the acceptor, which was the highest among the previously reported OSCs based on c-HBC derivatives. The results indicated that HBC-4-PDI may serve as a good non-fullerene acceptor for OSCs.

Optimization of Corrosion Behaviour of Blended TiO2 /ZnO Coating on SUS 304 using Taguchi Method

Objectives: To determine the best combination of blends of TiO2 /ZnO coated on SUS for obtaining a minimum corrosion rate. Methods: Different TiO2 /ZnO thin film blends are coated on SUS 304 substrates. The sol-gel dip-coating process is used for coating application. Also, withdrawal rates, calcination temperature, and doping percentage are the parameters used for the study of the anti-corrosion property. L9 array, using the Taguchi method, is applied for the design of the experiment. P.G-Lyte 1.0 model was used for the anticorrosion test. The Potentiosatic polarization method was applied for anti-corrosion testing. Findings: The results show that the percentage of ZnO doping (60%, 40%, and 20%) is the most significant factor in controlling the corrosion of the sample with plate number 1. The withdrawal rate (0.5 mm/sec, 1 mm/sec, and 1.5 mm/sec) has a minimal impact on the corrosion rate of the coated sample. The calcination temperature (300◦C, 400◦C, and 500◦C) has a greater impact than the withdrawal rate. There is a good agreement between the predicted and actual corrosion current. Novelty: Investigation of mechanical properties like corrosion resistance is essential for increasing the durability of automobile components by applying a coating of blends of TiO2 and ZnO with a rare blending combination that was not applied before for the investigation. In this research, efforts are made to reduce the corrosion rate by applying different blends of TiO2 and ZnO. Also, withdrawal rate and calcination temperature are varied in the process which was also not considered in the earlier studies. Keywords: Taguchi method; Corrosion current; Signal to Noise ratio; Coating; Design of experiments

In vitro cytotoxicity and wound healing activities of quaternary blended carboxymethyl cellulose-hydroxypropyl methylcellulose composite film

In vitro cytotoxicity and wound healing activities of quaternary blended carboxymethyl cellulose-hydroxypropyl methylcellulose composite film

Microwave dielectric characterization studies of PVDF-TrFE-Nafion blended films

The solution-based casting method fabricates the free-standing pure PVDF-TrFE, PVDF-TrFE-Nafion blended films and tests them for structural, morphological, and microwave studies. The X-ray diffraction pattern and FTIR spectrum confirmed the formation of the ferroelectric β-phase of PVDF-TrFE. The surface morphology of blended films is studied by scanning electron microscope (SEM), and noticeable changes in the morphological features are observed in the blended films resulting from the differences in the nucleation process in these films. Then using the open-ended coaxial probe method, the complex permittivity measurements were carried out over a large frequency range, from 0.5 GHz to 50 GHz. These results were verified with the Transmission-Reflection method using a rectangular waveguide in the X-band and Ku-band frequency range. The microwave absorption properties of the blends are also studied in the same frequency range. The stability of the dielectric properties and low microwave absorption indicates that the blending of PVDF-TrFE with Nafion results in a new potential material for high frequency flexible capacitor applications.

Advanced Molecular Design for Efficient Multicolor Electrochemiluminescence and Amplified Spontaneous Emission Based on Tetra‐BF2 Complexes

AbstractAdvanced organoboron dyes, incorporating tetra‐boron difluoride (tetra‐BF2) moieties, are developed, demonstrating efficient electrochemiluminescence (ECL) emissions in the green to orange regions through direct ion annihilation. By introducing diverse alkyl modifications in the molecules, luminescence color tuning is achieved via alterations in conjugation and bending angle. A photoluminescence quantum yield of 100% in dilute solutions is successfully achieved. Notably, the introduction of alkyl groups to the methine side stabilizes the radical ionic state, resulting in a high ECL efficiency of 74% through an efficient radical‐ion annihilation pathway. The key factor is that the energy of the annihilation reaction exceeds the S1 energy required for luminescence. Spin density calculations further elucidate the substituent effects on the radical ions of complexes. Moreover, the lasing properties of these materials in the solution‐processed blend films are investigated, revealing a low amplified spontaneous emission (ASE) threshold (Eth) of 6.40 ± 0.24 µJ cm−2, which is notably lower among organic laser materials. This is attributed to their large Stokes shifts and high quantum yield. The excellent ECL and ASE performances establish these materials as a valuable addition to the existing library of organoboron dyes, offering fresh insights into the development of organic solid‐state lasers.

Flexible MXene-based Janus film with superior heat dissipation capability for ultra-efficient electromagnetic interference shielding and Joule heating

The incorporation of polymers into MXene-based functional materials has been proven to be an effective strategy for improving their flexibility and mechanical properties. However, insulating polymers inevitably sacrifice the conductivity of MXene, resulting in a deterioration of electromagnetic interference (EMI) shielding performance. In this work, inspired by Janus structure, an asymmetric flexible film composed of the carboxylated styrene-butadiene rubber (XSBR) with magnetic boron nitride nanosheets (mBNNS) layer and the MXene layer is developed through a casting plus spraying approach. The resulting mBNNS/XSBR@MXene (BXM) Janus film demonstrates the characteristic of “one side insulation, one side conductivity”, with the conductivity of 2746 S cm−1 on the MXene side and surface resistivity of 4.9 × 1013 Ω on the mBNNS/XSBR side. Profit from the designed Janus architecture, the EMI shielding effectiveness and in-plane thermal conductivity of the BXM Janus film reach 74.55 dB and 8.45 W m−1 K−1 when the total mass fraction of mBNNS and MXene is 50 wt%, which is 148 % and 43.46 % higher than that of the BXM blend film without Janus structure. Moreover, the BXM Janus film exhibits low applied voltage (∼3.0 V) driven Joule heating performance with a response time of less than 10 s, a saturation temperature of 133.7 °C, and long-term steady reliability. Meanwhile, the BXM Janus film possesses good mechanical properties and excellent EMI shielding stability. Therefore, this work provides an effective strategy to fabricate flexible MXene-based multifunctional film for EMI shielding, heat dissipation, and thermal management applications.

A Novel Fabrication of Heterogeneous Saponified Poly(Vinyl Alcohol)/Pullulan Blend Film for Improved Wound Healing Application.

In this study, a novel film of poly(vinyl alcohol) (PVA)/pullulan (PULL) with improved surface characteristics was prepared from poly(vinyl acetate) (PVAc)/PULL blend films with various mass ratios after the saponification treatment in a heterogeneous medium. According to proton nuclear magnetic resonance (1H-NMR), Fourier transform infrared, and X-ray diffraction results, it was established that the successful fabrication of saponified PVA/PULL (100/0, 90/10, and 80/20) films could be obtained from PVAc/PULL (100/0, 90/10, and 80/20) films, respectively, after 72 h saponification at 50 °C. The degree of saponification calculated from 1H-NMR analysis results showed that fully saponified PVA was obtained from all studied films. Improved hydrophilic characteristics of the saponified films were revealed by a water contact angle test. Moreover, the saponified films showed improved mechanical behavior, and the micrographs of saponified films showed higher surface roughness than the unsaponified films. This kind of saponified film can be widely used for biomedical applications. Moreover, the reported saponified film dressing extended the lifespan of dressing as determined by its self-healing capacity and considerably advanced in vivo wound-healing development, which was attributed to its multifunctional characteristics, meaning that saponified film dressings are promising candidates for full-thickness skin wound healing.