Polyethylene Terephthalate Film Research Articles

MXene/Bacterial Cellulose Hybrid Materials for Sustainable Soft Electronics

This work evaluated bacterial cellulose (BC) as a possible biodegradable soft electronics substrate in comparison to polyethylene terephthalate (PET), while also focusing on evaluating hybrid MXene/BC material as potential flexible electronic sensor. Material characterization studies revealed that the BC material structure consists of nanofibers with diameters ranging from 70 to 140 nm, stacked layer-by-layer. BC samples produced are sensitive to post-treatment with isopropanol resulting in a change of structural and mechanical properties. The viscoelastic properties of the BC substrates have been studied experimentally in comparison with the PET film. Aged BC substrate showcased similar viscoelastic properties stability, while exhibiting better properties above 70 °C, with total storage modulus change of −15% and loss modulus change of 21%. MXenes prepared using the Minimally Intensive Layer Delamination (MILD) method were screen-printed onto BC substrates and PET films to form MXene/BC (MX/BC) and MXene/PET (MX/PET) devices. The electrical properties results showcased different resistive behavior on both BC and PET substrate samples with different impedance moduli. MX/PET presented lower sheet resistance of around 156 Ω·sq−1, while MX/BC was 2733 Ω·sq−1. Finally, the MX/BC and MX/PET devices were subjected to repeatable quasi-static load tests and the piezoresistive sensing behavior of the devices has been reported.

A Double‐Arch‐Structured Hybrid Triboelectric and Piezoelectric Nanogenerator Based on Polyvinylidene Fluoride/Graphene Oxide Composite Films

In this study, a methodology for fabricating double‐arch triboelectric and piezoelectric composite nanogenerators using polyvinylidene fluoride (PVDF) and graphene oxide (GO) is presented. Initially, nanofiber films comprising PVDF/GO are synthesized through electrostatic spinning. Subsequently, the PVDF/GO film is integrated with cotton fibers and a copper electrode to construct the triboelectric layer. In contrast, another portion of the PVDF/GO film, alongside a copper electrode, comprises the piezoelectric layer, with the central copper electrode acting as a common electrode. Finally, a double‐arch structure is established by employing polyethylene terephthalate film to facilitate synergistic operation between the triboelectric and piezoelectric layers. In the experimental results, it is indicated that the maximum open‐circuit voltage and short‐circuit current of the triboelectric layer of the double‐arch structure are 330 V and 36 μA, respectively, representing increases of 44% and 50% compared to those of the sandwich triboelectric structure. Additionally, the maximum open‐circuit voltage and short‐circuit current of the piezoelectric layer are 22 V and 4 μA, respectively, reflecting enhancements of 57% and 100% over those of conventional sandwich piezoelectric structures. The output power of the double‐arch composite nanogenerator is capable of lighting up 120 light‐emitting diodes. Thus, this composite nanogenerator shows great potential as an environmentally friendly energy source.

Enhancing PET degradation efficiency through fusing carbohydrate-binding modules in LCC-ICCG

Polyethylene terephthalate (PET) is a largely-produced polymer worldwide. However, its extensive waste generation and resistance to degradation pose significant environmental concerns. Consequently, there is considerable interest in researching enzymatic degradation of PET. Relevant studies have shown that the addition of a carbohydrate binding module (CBM) can increase the affinity between the enzyme and the substrate, enhancing the enzyme's degradation ability. In order to develop more efficient PET hydrolytic enzymes, this study introduced carbohydrate binding domains (CBMs) from different families with different substrate affinities into the PET-degrading enzyme LCC-ICCG. High crystallinity PET powder and amorphous PET film were used as substrates to characterize the degradation efficiency of the modified enzymes, aiming to explore the enzyme with the optimal degradation ability. The results showed that the fusion of type B CBM reduced the degradation rate and Tm value of the enzyme towards PET, while the introduction of type A and type C CBMs significantly improved the degradation rate of the enzyme towards the film-like substrate. The degradation rate and Tm value of PET were also enhanced, especially with the fusion enzyme LCC-ICCG-CBM9-2, which showed an over 10-fold increase in the degradation rate compared to the original enzyme LCC-ICCG. Therefore, this study demonstrates that by introducing type A and type C CBMs, the degradation rate and thermal stability of LCC-ICCG towards film-like PET can be improved, addressing the issue of its low activity and enabling more effective PET degradation. This research provides support for plastic degradation technology and contributes to environmental conservation efforts.

Determining the constant diffusion coefficient by Fourier series solution of the diffusion equation

The purpose of this study was to obtain the diffusion coefficient by calculating directly from the Fourier series solution of the diffusion equation, which has not been studied so far. The Fourier series solution is the sum of a steady-state solution and a transient solution. The steady-state solution is a linear function of distance. The transient solution is the product of a distance function and a time function. The Fourier sine series solution, a function of distance only, is negative for the steady-state solution. For the sublimation diffusion of disperse dye in paste into polyethylene terephthalate (PET) film using the film-roll method, the constant surface concentration and the diffusion distance were determined from the quadratic regression curve for the concentration distribution at a long time. The concentration distribution of the transient solution is a downwardly convex curve with negative values. The concentration distribution of the Fourier series solution is also a downwardly convex curve. The diffusion coefficient in the exponential term, a function of time only, was determined from the value of the exponential term obtained by the surface concentration and the diffusion distance. The constant diffusion coefficients determined from the Fourier series solution are reliable because they are very similar to those obtained from the error function solution and have excellent linearity of the linear regression lines for their Arrhenius plots.

Unravelling biochemical and molecular mechanism of a carboxylesterase from Dietzia kunjamensis IITR165 reveal novel activities against polyethylene terephthalate

Plastics and plasticizers accumulate in the ecological niches affecting biodiversity, and human and environmental health. Bacteria degrading polyethylene terephthalate (PET) were screened and PETases involved in PET degradation were characterized. Here, we identified a carboxylesterase Dkca1 of 48.44 kDa molecular mass from Dietzia kunjamensis IITR165 shown to degrade amorphous PET film into bis(2-hydroxyethyl) terephthalate (BHET) and terephthalic acid (TPA) formed 64.35 μM and 35.26 μM, respectively within 96 h at 37 °C as revealed by LC-MS analysis showed significant PET hydrolase activity similar to reported PETases. SEM analysis confirms the surface erosion as cavities and holes. Dkca1 also hydrolysed BHET and dibutyl phthalate (DBP) at a concentration of 1 mM within 3 h indicating its versatility. Fluorescence quenching shows Dkca1 protein has a maximum affinity (Kd) towards BHET (86.55 μM) than DBP (134.2 μM). The protein demonstrated high stability under temperatures above 40 °C and at the pH range of 6.0–9.0. Moreover, Amino acid composition showed that the Dkca1 enzyme belongs to family VII carboxylesterase containing conserved catalytic triad of Ser183-Glu289-His378 with pentapeptide motif GXSAG and an oxyanion hole H103GGG106, sharing 37.47 % and 32.44 % similarity with a PET hydrolase TfCa from Thermobifida fusca and PAE hydrolase CarEW from Bacillus sp. K91, respectively. A docking study revealed that ligand PET, BHET, and DBP showed favourable binding in the catalytic pocket of the Dkca1 protein.

Comparison of formulas derived from Fourier series solution of diffusion equation

The first Fourier series solution satisfying the boundary condition of zero concentration at the diffusion distance was derived by assuming that the solution consists of a steady-state solution and a transient solution. The first total amount which has passed through the first layer surface was derived from the first Fourier series solution. When the diffusion distance is large, the exponential term in the first total amount cannot be zero. For the sublimation diffusion of disperse dye in paste into polyethylene terephthalate film using the film-roll method, the plot of the first total amount against time was in good agreement with the quadratic regression curve. The second Fourier series solution satisfying the boundary condition of constant concentration at the diffusion distance was derived by assuming that the diffusion distance is the thickness of the first layer. The second total amount which has passed through the second layer surface was derived from the second Fourier series solution and is a linear function of time because the exponential term is zero due to the very small diffusion distance, the thickness of the first layer. The plot of the second total amount against time was in good agreement with the linear regression line. The time-lag formula was derived from the second total amount. The diffusion coefficients determined from the second total amount are much larger than those of the other three types. All four types showed excellent linearity in Arrhenius plot, but the activation energy for the time-lag formula is somewhat greater than the rest.

Generation of Active Amino Groups on the Surface of a Polyethylene Terephthalate Film and Their Quantitative Evaluation

Generation of Active Amino Groups on the Surface of a Polyethylene Terephthalate Film and Their Quantitative Evaluation

Structural, Morphological, and Optoelectronic Properties of RF Sputtered AZO Thin Films on Glass and Polymer Substrates: A Comparative Study

This paper investigates the thickness-dependent structural, morphological, and optoelectronic properties of Al-doped ZnO (AZO) thin films deposited on glass and flexible polyethylene terephthalate (PET) substrates via confocal magnetron sputtering. The film’s thickness ranged from 50 to 130 nm. X-ray diffraction results show that all AZO films on glass have better structural properties than those on PET. Furthermore, the (002) peak intensity and crystallite size on both substrates improved progressively with thickness. Field emission scanning electron microscopy and atomic force microscopy images revealed that the film morphology and surface roughness are dependent on substrate and thickness. According to the UV–vis-NIR measurement results, the air-referenced transmittance spectra of films on PET were slightly lower than those on glass; however, compared to films on glass, the substrate-referenced transmittance of PET films was higher. Moreover, for both substrates, it is found that the bandgap of fabricated thin films decreases with thickness. Photoluminescence spectra show that for glass and PET substrates, the total luminescence of AZO decreases with increasing film thickness and that green and red emissions are absent from AZO films deposited on PET substrates. AZO films deposited on glass substrates exhibit superior electrical and optoelectronic characteristics.

Engineering dual-functional and thermophilic BMHETase for efficient degradation of polyethylene terephthalate

Polyethylene terephthalate (PET) biodegradation is hindered by the intermediates bis (2-hydroxyethyl) terephthalate (BHET) and mono (2-hydroxyethyl) terephthalate (MHET). BMHETase, a thermophilic hydrolase identified from the UniParc database, exhibits degradation activity towards both BHET and MHET. BMHETase showed higher activity on BHET than LCCICCG and FASTPETase at temperatures ranging from 50 to 70℃. To enhance its activity in degrading MHET, BMHETase was engineered to mimic Ideonella sakaiensis MHETase. The resulting 6-point mutant’s activities on MHET and BHET were 8 and 2 times those of the WT, with both optimal temperatures increased by 5℃. This enhancement may be attributed to the BMHETase6M’s intensified binding ability with MHET and enlarged binding pocket. When combined with LCCICCG, BMHETase6M achieved complete degradation of MHET in PET films to terephthalic acid, indicating broad application potential. These findings suggest that BMHETase6M holds promise as a candidate for enhancing PET biodegradation efficiency and plastic waste management.

Influence of Rolling Speed on the Mechanism of Adiabatic Shear Band Formation and Plastic Flow in Polyethylene Terephthalate Films

Influence of Rolling Speed on the Mechanism of Adiabatic Shear Band Formation and Plastic Flow in Polyethylene Terephthalate Films

Roll-to-Roll SiOx Synthesis on Polyethylene Terephthalate Film by Atmospheric-Pressure Plasma-Assisted Chemical Vapor Deposition

Silicon oxide (SiOx) coatings are attracting significant attention and are widely used in industrial applications. They can be prepared by plasma-assisted chemical vapor deposition (PACVD). PACVD at atmospheric pressure (AP-PACVD) is often employed to synthesize SiOx coatings, but it has generally not been scaled up to an industrially viable level. In the present work, a SiOx coating was continuously deposited onto a polyethylene terephthalate film using industrial-scale roll-to-roll type AP-PACVD. 1,1,3,3-Tetramethyldisiloxane (TMDSO) and tetraethoxysilane (TEOS) were selected as precursors. The elemental compositions and chemical structures of the SiOx coatings were characterized, and oxygen and water-vapor transmission rates were measured. The SiOx coating using TEOS exhibited better barrier properties than that using TMDSO, corresponding to the high oxygen content, high SiO2 content, and high siloxane network content in the SiOx coating.

A 3D printed serrated contact structure triboelectric nanogenerator for swimming training safety monitoring

The wearable electronic devices integrated with 3D printing have attracted much attention, but the continuous power supply demand and limited application scenarios have limited their development. Here, we propose a 3D printed serrated contact structure triboelectric nanogenerator (S-TENG) designed for mechanical energy harvesting and swimming training safety monitoring. Leveraging the advancements in 3D printing technology, we created a flexible, lightweight sensor integrated with polytetrafluoroethylene (PTFE) and polyethylene terephthalate (PET) films on a serrated substrate. This configuration enhances the contact surface area, leading to a significant improvement in energy harvesting efficiency compared to flat structures. Specifically, the serrated structure resulted in a 64 %, 63 %, and 47 % increase in open-circuit voltage (Voc), short-circuit current (Isc), and transferred charge (Qsc), respectively, owing to the contact area and unique surface functional structure. The S-TENG device exhibits excellent performance under various bending angles, with Voc, Isc, and Qsc reaching up to 98.04 V, 4.35 μA, and 38.51 nC at 90° bending. Additionally, the S-TENG maintains stable output in different humidity environments due to its fully encapsulated design, ensuring reliable operation in aquatic settings. The S-TENG can accurately measure elbow swing amplitude and frequency, providing valuable real-time data for athletes and coaches. The S-TENG's ability to detect irregular movements and potential drowning incidents underscores its promise in enhancing swimmer safety. This research demonstrates the S-TENG's utility in both energy harvesting and motion monitoring, paving the way for advanced wearable sports sensors in various athletic disciplines.

Optical and structural transformations in polyethylene terephthalate (PET) films subjected to Ag[formula omitted]-ion implantation and subsequent Au[formula omitted]-ion irradiation

We report on the dual effects of ion implantation and swift heavy ion on the optical and structural characteristics of polyethylene terephthalate (PET) films using UV–Vis spectrophotometry, FTIR and X-ray diffraction measurements. Samples were first implanted with 150 keV Ag+-ions at different fluences of 1 ×1016, 5 ×1016, and 1 ×1017 ions/cm2, and thereafter irradiated with 30 MeV Au7+-ions at different fluences, while analysing elemental depth profile in situ on the Time of Flight Heavy Ions Elastic Recoil Detection (ToF-Hi-ERDA) instrument. The elemental depth profile measurements showed considerable atomic depletion of hydrogen from 36% down to below 6% and oxygen from 18% to about 5%. The proportion of carbon increased from 45% to over 87%. The optical bandgap decreased with increasing ion implantation fluence and reduced even further on irradiation with 30 MeV 197Au7+-ions. The most notable outcome of the implantation was the onset of the precipitation of gold nanoparticles (Au-NPs) in the PET matrix, marked by Localised Surface Plasmon Resonance effects, coincided with a relatively significant drop in the bandgap energy. This latter effect could only be best explained as the result of these Au-NPs in the PET. This suggests that optical bandgap tuning in polymer films, usually achievable through high fluence implantation at low energy (i.e., keV), could also be realized through low fluence irradiation with MeV energy ions. It is surmised that, for the noble metals, NP-induced bandgap modification in PET precludes the need for high fluence to achieve the same. This has the obvious advantage of bandgap alterations at much lower structural damage to the target polymer. As reported by FTIR results, one can observe structural changes with the formation of new chemical bonds on thin films. X-ray diffraction results exhibited one prominent peak corresponding to the (100) plane, which varies in intensity with increased implantation fluence, suggesting a change in the crystallinity of the PET. The decrease in (100) peak or crystallinity was well connected with the presence and decrease of 847, 970, and 1471 cm−1 peaks, which were assigned to the ethylene glycol molecular groups.

Unlocking a Key Residue in a Lipase for Efficient Polyethylene Terephthalate (PET) Hydrolysis and Influencing Depolymerization Product Profiles

Polyethylene terephthalate (PET) pollution is a global challenge. Advancing the bioprospecting of PET‐degrading enzymes through metagenomics and using computational and functional methods to identify key positions influencing the catalytic rate and selectivity are part of the solution. Here, we report PETase activity in the metagenomic lipase LipMRD9, which exhibits peak activity at 30 °C and pH 9.0 and has a denaturation temperature of 42 °C. In addition to acting on long‐chain triglycerides (up to 13 units (U)/mg, pH 8.0, 30 °C) and a wide range of 34 other esters (up to 228 U/g), LipMRD9 hydrolyses mono(2‐hydroxyethyl) terephthalate (57 U/g) and bis(2‐hydroxyethyl) terephthalate (131 U/g). It also efficiently deconstructs GoodFellow amorphous submicro‐ and nanosized PET particles (984/2238 µM degradation products at 30/40 °C, pH 7.0, 21.5 h) and films (112/198 µM degradation products at 30/40 °C, pH 7.0, 7 days). Through molecular modelling and experimental analysis, the active site of LipMRD9 was revealed, identifying a key residue contributing to its PETase activity compared with those of its closest homologues. This residue plays a crucial role in determining the distinct profiles of degradation products from PET hydrolysis and should be studied in other PETases for its influence on the catalytic process.

Degradation of polyethylene terephthalate (PET) plastics by wastewater bacteria engineered via conjugation.

Wastewater treatment plants are one of the major pathways for microplastics to enter the environment. In general, microplastics are contaminants of global concern that pose risks to ecosystems and human health. Here, we present a proof-of-concept for reduction of microplastic pollution emitted from wastewater treatment plants: delivery of recombinant DNA to bacteria in wastewater to enable degradation of polyethylene terephthalate (PET). Using a broad-host-range conjugative plasmid, we enabled various bacterial species from a municipal wastewater sample to express FAST-PETase, which was released into the extracellular environment. We found that FAST-PETase purified from some transconjugant isolates could degrade about 40% of a 0.25 mm thick commercial PET film within 4 days at 50°C. We then demonstrated partial degradation of a post-consumer PET product over 5-7 days by exposure to conditioned media from isolates. These results have broad implications for addressing the global plastic pollution problem by enabling environmental bacteria to degrade PET.

Measuring PETase enzyme kinetics by single-molecule microscopy

Polyethylene terephthalate (PET) is one of the most widely produced man-made polymers and is a significant contributor to microplastics pollution. The environmental and human health impacts of microplastics pollution have motivated a concerted effort to develop microbe- and enzyme-based strategies to degrade PET and similar plastics. A PETase derived from the bacteria Ideonella sakaiensis was previously shown to enzymatically degrade PET, triggering multidisciplinary efforts to improve the robustness and activity of this and other PETases. However, because these enzymes only erode the surface of the insoluble PET substrate, it is difficult to measure standard kinetic parameters, such as kon, koff, and kcat, complicating interpretation of the activity of mutants using traditional enzyme kinetics frameworks. To address this challenge, we developed a single-molecule microscopy assay that quantifies the landing rate and binding duration of quantum dot-labeled PETase enzymes interacting with a surface-immobilized PET film. Wild-type PETase binding durations were well fit by a biexponential with a fast population having a 2.7 s time constant, interpreted as active binding events, and a slow population interpreted as nonspecific binding interactions that last tens of seconds. A previously described hyperactive mutant, S238F/W159H had both a faster apparent on-rate and a slower off-rate than wild-type PETase, potentially explaining its enhanced activity. Because this single-molecule approach provides a more detailed mechanistic picture of PETase enzymatic activity than standard bulk assays, it should aid future efforts to engineer more robust and active PETases to combat global microplastics pollution.

Measurement of the water vapor transmission rate at temperatures above 100 °C

ABSTRACT Water vapor transmission rate (WVTR) and water vapor permeability coefficient were measured at temperatures between 110 and 138°C using the modified cup method. The cup, placed in a Highly Accelerated Stress Test chamber, allowed water vapor to permeate the sample film attached to the cup. The WVTR was determined based on the increase in mass of the cup. To prevent sample damage during measurement, a cup with a pressure adjustment mechanism was utilized. Carrier-incorporated phosphorus pentoxide was used as the desiccant instead of anhydrous calcium chloride to ensure a consistent moisture absorption rate, especially at high temperatures. The water vapor permeability coefficients for the polycarbonate, polyimide, and adhesive films were distributed on an approximately straight line in the Arrhenius plot. Additionally, the Arrhenius plots for the polyethylene terephthalate and polyethylene naphthalate films captured the permeability bending point near the glass transition temperature. To accurately measure the high-temperatureWVTR, upper and lower limits were established for the weighing interval, cup mass gain, and WVTR measurement range.

Photolytic decomposition of PFOS by electrospun nanofiber composites of Fe(III)/PVDF Under UV-C light

Per- and polyfluoro alkyl substances (PFAS) are emerging pollutants that have contaminated various water streams of the world. Besides polluting the environment, it is related to several human diseases, including cancer. Various methods have been proposed to remove PFAS from water streams including, photocatalytic or photolytic decomposition of PFAS which decomposes PFAS in a quasi-perpetual fashion and does not generate secondary pollution. In this work, perfluoroctane sulfonic acid (PFOS) is used as a model PFAS to study its photolytic decomposition by nanofiber composites (NFC) of Fe (III) and polyvinylidene fluoride (PVDF) under ultraviolet (UV)-C light. The nanofiber composite was fabricated using an electrospinning technique with PVDF and iron precursor on the conductive surface of indium tin oxide (ITO) coated polyethylene terephthalate (PET) film. The composite was characterized with SEM-EDX, AFM, XRD, and TGA. It was found that a significant amount, 70 % of aqueous PFOS solution is decomposed by the composites in the presence of traces of hydrogen peroxide and UV-C light. The kinetics of PFOS degradation was fit with pseudo-first order rate constant of 0.056 hr−1. It is proposed that PFOS binds with Fe(III) to form an unstable complex that is decomposed under UV-C light and Fe(III) is reduced Fe(II). Hydrogen peroxide provides the simultaneous benefits of further decomposing the PFOS complex and regenerating Fe(III). The overall results suggest that this nanofiber composite can be used for the photolytic decomposition of PFOS. It is also revealed that two composite mats showed the optimal performance and the increase in concentration of hydrogen peroxide increased the degradation of PFOS monotonically.

Wideband optically transparent absorber based on multilayer ITO films with high absorption rate

In this paper, a wideband optically transparent absorber based on multilayer indium tin oxide (ITO) films is designed, fabricated, and measured. The structure uses polyethylene terephthalate (PET) and ITO films to replace the dielectric substrate and metal pattern of the traditional absorber to achieve optical transparency characteristics. The absorption of the proposed absorber is above 90% from 4.92 to 24.55 GHz and exceeding 95% in the range of 5.74 ∼ 21.85 GHz, respectively, under normal transverse electric (TE) and transverse magnetic (TM) polarized incidences. Moreover, it shows outstanding stability with various incident angles over a wide range. A prototype of the proposed absorber is fabricated and experimentally verified, with good measurement results. The optical transparency and great absorption performance make the absorber a promising candidate for transparent electromagnetic compatibility.

Surface modification of polyethylene terephthalate films by direct fluoridation for flexible electronic applications

In this study, a comprehensive investigation was carried out to analyse the effects of direct fluorination on the structural, morphological, wettability, thermal and optical properties of polyethylene terephthalate (PET) films. The results show significant changes in surface composition and structure, as well as changes in surface morphology induced by fluorination. In addition, an increase in surface hydrophilicity and surface free energy were observed after fluorination. Although there appeared to be a slight decrease in thermal stability of the fluorinated PET films, they exhibited increased optical transmittance in the UV–visible spectrum compared to the original PET films. These findings demonstrate how fluorinated PET films have better surface qualities, which makes them appropriate for a range of uses including printing, coating, and optoelectronics.