Preparation of the Transferred Sheets with Cellulose Nanofiber Thin Film and Their Gas Barrier Characteristics

The effects of excimer light irradiation on polysilazane coatings formed on PET films with vacuum-evaporated SiO2 coatings and the effects of these coatings on gas barrier characteristics have been investigated. The temperature during light irradiation has a large effect on the coating’s molecular structure and gas barrier characteristics. When irradiation was performed at 100℃, the polysilazane coating transformed into a silica coating, and a compact silica coating at a much lower temperature than with heat treatment alone was produced. Surface irregularities in the vapor-deposited silica coating were smoothed out by the formation of a polysilazane coating, which was transformed into a compact silica coating when irradiated with light, resulting in a significant improvement in the gas barrier characteristics. The water vapor permeability of the thin coating irradiated with excimer light at 100℃ showed only 0.04 g/m2•day (40℃, 90% RH). According to the results of investigation of temperature variation of water-vapor permeability, it is inferred that the developed film has an excellent gas barrier value, namely, 4.90 × 10–4 g/m2•day at 25℃. This gas barrier coated PET film is transparent and flexible, and can be used in the fabrication of flexible electronics. Also, the proposed fabrication method effectively provides a simple low-cost and low-temperature fabrication technique without the need for high vacuum facility.

The gas barrier film formation technique using simultaneous photo-irradiation and heat-treatment has been researched on alicyclic polyimide film coated with a polysilazane solution. A fine SiO2 thin film on polyimide film was formed at low temperatures, which greatly improved the substrate's gas barrier characteristics by this technique. The values of gas barrier characteristics depended on the substrate temperature at the time of photo-irradiation. For photo-irradiated thin film heat-treated to 150°C, the water vapor transmission rate and oxygen transmission rate fell below the equipment measurement limit of 0.02 g/m2/day and 0.02 cm3/m2/day, respectively. This polyimide film with a gas-barrier film coating has good transmittance in the region of visible light, heat resistance, and flexibility.

Gas barrier characteristics of a polysilazane film formed on an ITO-coated PET substrate

P-17 Preparation of the transferred sheets with cellulose nanofiber thin film and their gas barrier characteristics

Chapter 21 - Emerging role of nanomaterials in storage and packaging of agricultural products

순수한 점토 5 wt%를 포함하는 poly(vinyl alcohol)(PVA) 나노 복합체 필름을 수용액상에서 합성하였다. 합성된 PVA 복합체 필름에는 구조적으로 각각 다른 사포나이트(SPT), 몬모릴로나이트(MMT), 헥토라이트(SWN), 수용성 벤토나이트(PGV) 및 마이카(Mica) 등의 점토를 사용하였다. 이처럼 여러 가지 순수한 점토가 포함된 PVA 복합체 필름에 대해 열적-광학적 성질 및 모폴로지를 평가하였으며, 전자 현미경을 통해 관찰된 PVA 복합체 필름의 나노 구조에서는 점토가 매트릭스에 잘 분산된 부분도 있었지만, 일부에서는 뭉친 부분도 발견되었다. 점토를 사용한 PVA 복합체 필름의 경우에 열적 성질이나 가스 차단성을 증가시키는 데에는 매우 효과적이었지만, 이와는 반대로 광학 투명성에서는 그렇지 못하였다. Poly(vinyl alcohol) (PVA) hybrid films containing 5 wt% pristine clay mineral were synthesized in the water solution. The various PVA hybrid films were synthesized from structurally different pristine clays: saponite (SPT), montmorillonite (MMT), hectorite (SWN), hydrophilic bentonite (PGV), and mica (Mica). The thermo-optical properties and morphologies of the PVA hybrid films were evaluated with various pristine clays. The nanostructure of the hybrid films was observed using transmission electron microscopy, which showed that the clay layers were well dispersed into the matrix polymer, although some clusters or agglomerated particles were also detected. The addition of pristine clay was more effective with regard to improving the thermal properties and gas barrier characteristics, whereas the optical transparency of the PVA hybrid films deteriorated with pristine clay.

Chapter17 - Applications of nanotechnology in food sensing and food packaging

This study investigates the potential of Chirich (Asphodelus aestivus) tuber, one of Turkey’s natural resources, for sustainable bio-hybrid film production. Bio-hybrid films developed from Chirich tuber starch in composite form with polyvinyl alcohol (PVOH) were thoroughly examined for their physical, mechanical, and barrier properties. During the production process, twin-screw extrusion and hydraulic hot pressing methods were employed; the films’ optical, chemical, and barrier performances were analyzed through FT-IR spectroscopy, water vapor permeability, solubility, and mechanical tests. To evaluate the films’ durability against environmental factors and model their properties, advanced computational model algorithms such as Gradient Boosting Regression (GBR), Random Forest Regression (RFR), and AdaBoost Regression (ABR) were utilized. The results showed that the GBR algorithm achieved the highest accuracy with 99.92% R2 and presented the most robust model in terms of sensitivity to environmental factors. The results indicate that Chirich tuber-based bio-hybrid films exhibit significantly enhanced mechanical strength and barrier performance compared to conventional corn starch-based biodegradable polymers. These superior properties make them particularly suitable for industrial applications such as food packaging and medical materials, where durability, moisture resistance, and gas barrier characteristics are critical. Moreover, their biodegradability and potential for integration into circular economy frameworks underscore their environmental sustainability, offering a viable alternative to petroleum-derived plastics. The incorporation of ML-driven optimization not only facilitates precise property prediction but also enhances the scalability of bio-hybrid film production. By introducing an innovative, data-driven approach to sustainable material design, this study contributes to the advancement of bio-based polymers in industrial applications, supporting global efforts to mitigate plastic waste and promote environmentally responsible manufacturing practices.

Mostly, food packaging employs synthetic materials obtained from nonrenewable sources. These packaging materials are based on petrochemicals and cause substantial environmental problems by producing massive amounts of non-biodegradable solid wastes. Edible coatings and films are considered as the potential solution to these problems of non-biodegradable packaging solid wastes for maintaining food-environment interactions, retaining food quality, and extending shelf life. In addition, edible coatings and films offer prevention from microbial spoilage of packed foods by controlling moisture and gas barrier characteristics. Increasing environmental concerns and consumer demands for high-quality eco-friendly packaging have fueled the advancement of innovative packaging technologies, for instance, the development of biodegradable films from renewable agricultural and food processing industry wastes. Therefore, the current chapter presents the application of edible coatings and films as an alternative to conventional packaging, emphasizing the fundamental characterization that these biodegradable packaging should hold for specific applications such as food preservation and shelf life enhancement. The primary employed components (e.g., biopolymers, bioactive, and additives components), manufacturing processes (for edible films or coatings), and their application to specific foods have all been given special consideration in this chapter. Besides, a future vision for the use of edible films and coatings as quality indicators for perishable foods is presented.

Polyethylene/graphene oxide composites toward multifunctional active packaging films

Gas permeation and selectivity of poly(dimethylsiloxane)/graphene oxide composite elastomer membranes

In this research, linear low-density polyethylene (PE-LLD), cast polypropylene (PPcast), and bioriented coextruded polypropylene (BOPP) were used as polymeric materials. Permeability, diffusivity, and solubility of N2, O2, and CO2 through above polymers were obtained at different temperatures. The structure and thermal–mechanical features of the films were characterized by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The permeability, diffusivity, solubility, and their temperature dependency were studied by correlations with gas molecule properties. The highest permeation coefficients (>3.8 × 10−8 cm3 cm−1 s−1 bar−1) are obtained for PPcast at 60 °C. Activation energy for permeation follows the sequence: N2 > O2 > CO2 for PE-LLD and PPcast. On the other hand, the diffusion activation energy follows the order: O2 > CO2 > N2 and N2 > CO2 > O2 for PE-LLD and PPcast, respectively. In the case of BOPP, activation energy follows the sequence: O2 > CO2 > N2; CO2 > N2 > O2; and O2 > CO2 > N2 for permeation, diffusion, and heat of sorption, respectively.

<h2>Summary</h2> Regardless of their applications, polymers are still considered mechanically weak and functionally insufficient for certain demanding coating and adhesive uses. To address those issues, nanomaterials have been extensively studied as reinforcing fillers, which have been proven to effectively promote the performance of polymer coatings/adhesives. However, conventional nanofillers are expensive and non-biodegradable. Meanwhile, cellulose nanomaterials (CNMs), a class of nanomaterials produced from biomass feedstocks, can circumvent the drawbacks of conventional nanofillers. This review paper first focuses on the multi-functionalities CNMs bring to polymer coatings, including mechanical reinforcement (wear resistance and hardness enhancement), gas barrier, flame resistance, corrosion resistance, self-healing (controlled-release), optical regulation, self-cleaning/antifouling, and antimicrobial characteristics. Then we discuss the benefits of CNM addition to polymer adhesives, such as mechanical enhancement, curing promotion, volatile organic compound (VOC) suppression, and electrical conductivity. Finally, we provide insights into future research efforts with CNMs. The goal of this paper is to promote the pilot-scale study and commercial use of CNMs as multifunctional additives in green and sustainable polymer composite coating and adhesive formulations.

Synthesis, properties, and applications of graphene oxide/reduced graphene oxide and their nanocomposites

Semiconducting and insulating polymer blend transistors have been studied to improve their air stability and create stretchable devices for skin electronics. Electron-transporting (or n-type) semiconducting polymers have significant problems regarding their device stability and performances. In this study, we tried to solve the stability issue of the n-type organic thin-film transistors (OTFTs). In order to extend the device lifetime, polyacrylonitrile (PAN) was introduced as an additive to the typical n-type naphthalenediimide (NDI)-based polymer, namely, P(NDI2T-OD) or N2200. PAN was well mixed with P(NDI2T-OD) to produce homogeneous solutions in chloroform/chlorobenzene mixtures when the PAN proportion was less than 5 wt%. The stability of the OTFTs stored in air was evaluated based on the electron mobility μe, threshold voltage Vth, and Ion/Ioff ratio. Adding a small amount of PAN can significantly improve the stability and μe values of the OTFTs probably due to the gas barrier and water trapping characteristics of the PAN.