scholarly journals Production of Hydrophobic Zein-Based Films Bioinspired by The Lotus Leaf Surface: Characterization and Bioactive Properties

2019 ◽  
Vol 7 (8) ◽  
pp. 267 ◽  
Author(s):  
Luís ◽  
Domingues ◽  
Ramos
Keyword(s):  
Contact Angle ◽  
Essential Oil ◽  
Food Packaging ◽  
Surface Characterization ◽  
Antibacterial Properties ◽  
Complex Surface ◽  
Scanning Calorimetry ◽  
Water Contact ◽  
Lotus Leaf ◽  
Surface Patterns

Hydrophobic zein-based functional films incorporating licorice essential oil were successfully developed as new alternative materials for food packaging. The lotus-leaf negative template was obtained using polydimethylsiloxane (PDMS). The complex surface patterns of the lotus leaves were transferred onto the surface of the zein-based films with high fidelity (positive replica), which validates the proposed proof-of-concept. The films were prepared by casting method and fully characterized by Scanning Electron Microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC). The grammage, thickness, contact angle, mechanical, optical and barrier properties of the films were measured, together with the evaluation of their biodegradability, antioxidant and antibacterial activities against common foodborne pathogens (Enterococcus faecalis and Listeria monocytogenes). The zein-based films with the incorporation of licorice essential oil presented the typical rugosities of the lotus leaf making the surfaces very hydrophobic (water contact angle of 112.50°). In addition to having antioxidant and antibacterial properties, the films also shown to be biodegradable, making them a strong alternative to the traditional plastics used in food packaging.

scholarly journals Pullulan–Apple Fiber Biocomposite Films: Optical, Mechanical, Barrier, Antioxidant and Antibacterial Properties

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 870
Author(s):  
Ângelo Luís ◽  
Ana Ramos ◽  
Fernanda Domingues
Keyword(s):  
Contact Angle ◽  
Water Vapor ◽  
Water Contact Angle ◽  
Food Packaging ◽  
Antibacterial Properties ◽  
Consumer Products ◽  
Vapor Permeability ◽  
P Value ◽  
Water Contact ◽  
Biocomposite Films

More than 150 million tons of synthetic plastics are produced worldwide from petrochemical-based materials, many of these plastics being used to produce single-use consumer products like food packaging. The main goal of this work was to research the production and characterization of pullulan–apple fiber biocomposite films as a new food packaging material. The optical, mechanical, and barrier properties of the developed biocomposite films were evaluated. Furthermore, the antioxidant and antibacterial activities of the biocomposite films were additionally studied. The results show that the Tensile Index and Elastic Modulus of the pullulan–apple fiber films were significantly higher (p-value < 0.05) when compared to the pullulan films. Regarding the water vapor permeability, no significant differences (p-value < 0.05) were observed in water vapor transmission rate (WVTR) when the apple fiber was incorporated into the biocomposite films. A significant increase (p-value < 0.05) of water contact angle in both sides of the films was observed when the apple fiber was incorporated into pullulan, indicating an increase in the hydrophobicity of the developed biocomposite films. It is worth noting the hydrophobicity of the (rough) upper side of the pullulan–apple fiber films, which present a water contact angle of 109.75°. It was possible to verify the microbial growth inhibition around the pullulan–apple fiber films for all the tested bacteria.

scholarly journals Effect of Sonication on the Properties of Flaxseed Gum Films Incorporated with Carvacrol

2020 ◽  
Vol 21 (5) ◽  
pp. 1637
Author(s):  
Shiyuan Fang ◽  
Weiqiang Qiu ◽  
Jun Mei ◽  
Jing Xie
Keyword(s):  
Contact Angle ◽  
Food Packaging ◽  
Antioxidant Activities ◽  
Antioxidant Properties ◽  
Antibacterial Properties ◽  
Vapor Permeability ◽  
Scanning Calorimetry ◽  
Cross Sectional ◽  
Water Sorption Isotherm ◽  
Flaxseed Gum

Carvacrol is a natural compound known to be a highly effective antibacterial; however, it is a hydrophobic molecule, which is a limitation to its use within food packaging. Flaxseed gum (FG) films containing different contents of carvacrol (C) were produced by a film-casting method with sonication. The effects of sonication power and time on the properties of the FG-C films were investigated by measuring the film thickness, mechanical properties, contact angle, opacity, water vapor permeability (WVP), water sorption isotherm, Fourier transform infrared spectroscopy(FTIR), differential scanning calorimetry (DSC), antibacterial and antioxidant activities, and microstructure. The results showed that sonication power and time had significant effects on mechanical and barrier properties, film opacity, and degradability (p < 0.05). The tensile strength (TS) and elongation at break (EB) values exhibited an obvious improvement after sonication, and FG-0.5C-6030 had the lowest TS (33.40 MPa) and EB (4.46%) values. FG-C films formed a denser structure and the contact angle was improved as a result of sonication, which improved the integration of carvacrol into the FG matrix. In terms of microstructure, sonication resulted in a homogeneous and continuous crosssection of FG-C films, and regular surface and cross-sectional images were obtained through the highest acoustic intensity and longest time treatment. The FG films incorporated with carvacrol displayed antibacterial properties against Staphylococcus aureus, Vibrio parahaemolyticus, Shewanella putrefaciens, and Pseudomonas fluorescens, as well as increased antioxidant properties, and sonication was proven to enhance both of them.

scholarly journals Incorporation of Lipids into Wheat Bran Cellulose/Wheat Gluten Composite Film Improves Its Water Resistance Properties

Membranes ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 18
Author(s):  
Guanghui Shen ◽  
Guoxian Yu ◽  
Hejun Wu ◽  
Shanshan Li ◽  
Xiaoyan Hou ◽  
...  
Keyword(s):  
Composite Film ◽  
Wheat Bran ◽  
Food Packaging ◽  
Water Resistance ◽  
Wheat Gluten ◽  
Vapor Permeability ◽  
Scanning Calorimetry ◽  
Sem Images ◽  
Water Contact ◽  
Cross Sectional

This work evaluated the improvement effects of lipids incorporation on water resistance of composite biodegradable film prepared with wheat bran cellulose/wheat gluten (WBC/WG) using an alkaline–ethanol film forming system. Four types of lipids, paraffin wax (PW), beeswax (BW), paraffin oil (PO), and oleic acid (OA), were tested. We found that PW, BW, and PO incorporation at 5–20% improved water vapor permeability (WVP) and surface hydrophobicity of prepared films. Particularly, incorporation of 15% BW could best improve the water resistance properties of the film, with the lowest WVP of 0.76 × 10−12 g/cm·s·Pa and largest water contact angle (WCA) of 86.18°. Incorporation of OA led to the decline in moisture barrier properties. SEM images revealed that different lipids incorporation changed the morphology and of the composite film, and cross-sectional morphology indicated BW-incorporated film obtained more uniform and compact structures compared to other films. Moreover, Fourier transform infrared spectra indicated that the incorporation of PW or BW enhanced the molecular interactions between the film components, confirmed by the chemical shift of characteristic peaks at 3277 and 1026 cm−1. Differential scanning calorimetry results revealed that incorporation of PW, BW, and PO increased films’ melting point, decomposition temperatures, and enthalpy values. Furthermore, the presence of most lipids decreased tensile strength and elongation at the break of the film. Overall, the composite film containing 15% BW obtained the most promising water resistance performance and acceptable mechanical properties, and it thus most suitable as a hydrophobic biodegradable material for food packaging.

scholarly journals Surface Characterization, Antimicrobial Activity, and Biocompatibility of Autopolymerizing Acrylic Resins Coated with Reynoutria elliptica Extract

Plants ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1292
Author(s):  
Song-Yi Yang ◽  
Min-Kyung Kang
Keyword(s):  
Contact Angle ◽  
Antimicrobial Activity ◽  
Cell Viability ◽  
Water Contact Angle ◽  
Vickers Hardness ◽  
Surface Characterization ◽  
Acrylic Resin ◽  
Water Contact ◽  
Acrylic Resins ◽  
Vis Spectroscopy

We conducted surface characterization to assess the biocompatibility and investigate the antimicrobial activity against oral pathogens in autopolymerizing acrylic resins, coated with light-curable coating resin, containing various concentrations of Reynoutria elliptica extract (0, 200, 400, and 600 µg/mL). The R. elliptica extract powder was prepared using a freeze-drying technique. Further, a goniometer and microhardness tester were used to determine the water contact angle, and Vickers hardness, respectively; color measurements were performed on the uncoated and coated acrylic resin disks. The polyphenol content of the extracts from the coated acrylic resin disk was analyzed using UV-VIS spectroscopy. The antimicrobial activity of the coated acrylic resin disk against Streptococcus mutans and Candida albicans was observed for 24 and 48 h by measuring the optical density using spectrophotometry. In addition, biocompatibility was confirmed by testing the cell viability according to ISO 10993-5. The water contact angle, Vickers hardness, and color change values of the coated acrylic resin disks were not significantly different from the control. Polyphenol was detected in all experimental groups, with no significant differences between the experimental groups. The experimental groups exhibited significant antimicrobial activity against S. mutans and C. albicans compared to the control group, after 48 h of incubation. The cell viability between the control and experimental groups was not significantly different. The proposed coating resin containing R. elliptica extract is applicable on dental acrylic resins, due to their antimicrobial properties and excellent biocompatibility, with no deterioration of surface characteristics.

scholarly journals Strategies to Improve the Properties of Amaranth Protein Isolate-Based Thin Films for Food Packaging Applications: Nano-Layering through Spin-Coating and Incorporation of Cellulose Nanocrystals

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2564
Author(s):  
Amparo López-Rubio ◽  
Adriana Blanco-Padilla ◽  
Kristiina Oksman ◽  
Sandra Mendoza
Keyword(s):  
Contact Angle ◽  
Optical Properties ◽  
Cellulose Nanocrystals ◽  
Spin Coating ◽  
Food Packaging ◽  
Water Solubility ◽  
Protein Isolate ◽  
Water Soluble ◽  
Water Contact ◽  
Angle Measurements

In this work, two different strategies for the development of amaranth protein isolate (API)-based films were evaluated. In the first strategy, ultrathin films were produced through spin-coating nanolayering, and the effects of protein concentration in the spin coating solution, rotational speed, and number of layers deposited on the properties of the films were evaluated. In the second strategy, cellulose nanocrystals (CNCs) were incorporated through a casting methodology. The morphology, optical properties, and moisture affinity of the films (water contact angle, solubility, water content) were characterized. Both strategies resulted in homogeneous films with good optical properties, decreased hydrophilic character (as deduced from the contact angle measurements and solubility), and improved mechanical properties when compared with the neat API-films. However, both the processing method and film thickness influenced the final properties of the films, being the ones processed through spin coating more transparent, less hydrophilic, and less water-soluble. Incorporation of CNCs above 10% increased hydrophobicity, decreasing the water solubility of the API films and significantly enhancing material toughness.

scholarly journals Product and Process Fingerprint for Nanosecond Pulsed Laser Ablated Superhydrophobic Surface

Micromachines ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 177 ◽  
Author(s):  
Yukui Cai ◽  
Xichun Luo ◽  
Zhanqiang Liu ◽  
Yi Qin ◽  
Wenlong Chang ◽  
...  
Keyword(s):  
Contact Angle ◽  
Laser Ablation ◽  
Process Parameters ◽  
Superhydrophobic Surface ◽  
Surface Characterization ◽  
Pulsed Laser ◽  
Threshold Value ◽  
Machined Surface ◽  
Water Contact ◽  
Nanosecond Pulsed Laser

Superhydrophobic surfaces have attracted extensive attention over the last few decades. It is mainly due to their capabilities of providing several interesting functions, such as self-cleaning, corrosion resistance, anti-icing and drag reduction. Nanosecond pulsed laser ablation is considered as a promising technique to fabricate superhydrophobic structures. Many pieces of research have proved that machined surface morphology has a significant effect on the hydrophobicity of a specimen. However, few quantitative investigations were conducted to identify effective process parameters and surface characterization parameters for laser-ablated microstructures which are sensitive to the hydrophobicity of the microstructured surface. This paper proposed and reveals for the first time, the concepts of process and product fingerprints for laser ablated superhydrophobic surface through experimental investigation and statistical analysis. The results of correlation analysis showed that a newly proposed dimensionless functional parameter in this paper, Rhy, i.e., the average ratio of Rz to Rsm is the most sensitive surface characterization parameter to the water contact angle of the specimen, which can be regarded as the product fingerprint. It also proposes another new process parameter, average laser pulse energy per unit area of the specimen (Is), as the best process fingerprint which can be used to control the product fingerprint Rhy. The threshold value of Rhy and Is are 0.41 and 536 J/mm2 respectively, which help to ensure the superhydrophobicity (contact angle larger than 150°) of the specimen in the laser ablation process. Therefore, the process and product fingerprints overcome the research challenge of the so-called inverse problem in manufacturing as they can be used to determine the required process parameters and surface topography according to the specification of superhydrophobicity.

Fabrication of the Superhydrophobic Surface Using SU-8 Photoresist With Black Silicon

2011 ◽  
Author(s):  
Sang Eon Lee ◽  
Dongjin Lee ◽  
Jin-Ha Kim ◽  
Kang Won Lee ◽  
Kwang-Cheol Lee ◽  
...  
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Superhydrophobic Surface ◽  
Black Silicon ◽  
Geometrical Shape ◽  
Water Contact ◽  
Ion Etching ◽  
Lotus Leaf ◽  
Pdms Surface ◽  
Micro Structures

A novel change method of surface wettability using both micro- and nano-sized geometrical shape is presented in this paper. After the black silicon is formed in reactive ion etching, SU-8 mold is fabricated on top of the black silicon that has nano-sized holes. After the microfabrication of SU-8 photoresist mold, poly-dimethysiloxane (PDMS) is poured into the mold. As a result, the molded PDMS surface has both micro- and nano-sized structures, which is similar to lotus leaf. The diameter of cylindrical pillar micro structures ranges from 50 to 100 μm. The water contact angle of 150° is obtained on the molded PDMS surface with pillars diameter of 50 μm. The superhydrophobic surface made of micro- and nanostructures is straightforwardly formed, increasing water contact angle on the engineered surface.

Tailoring Surface Hydrophobicity of Commercial Polyimide by Laser-Induced Nanocarbon Texturing

2020 ◽  
Vol 8 (3) ◽  
Author(s):  
Moataz Abdulhafez ◽  
Angela J. McComb ◽  
Mostafa Bedewy
Keyword(s):  
Contact Angle ◽  
Surface Characterization ◽  
Surface Engineering ◽  
Processing Parameters ◽  
Surface Hydrophobicity ◽  
Spot Size ◽  
Contact Angles ◽  
Water Contact ◽  
Wide Range ◽  
Surface Nanostructure

Abstract The growth of laser-induced nanocarbons, referred to here as laser-induced nanocarbon (LINC) for short, directly on polymeric surfaces is a promising route toward surface engineering of commercial polymers. This paper aims to demonstrate how this new approach can enable achieving varied surface properties based on tuning the nanostructured morphology of the formed graphitic material on commercial polyimide (Kapton) films. We elucidate the effects of tuning laser processing parameters on the achieved nanoscale morphology and the resulting surface hydrophobicity or hydrophilicity. Our results show that by varying lasing power, rastering speed, laser spot size, and line-to-line gap sizes, a wide range of water contact angles are possible, i.e., from below 20 deg to above 110 deg. Combining water contact angle measurements from an optical tensiometer with LINC surface characterization using optical microscopy, electron microscopy, and Raman spectroscopy enables building the process–structur–property relationship. Our findings reveal that both the value of contact angle and the anisotropic wetting behavior of LINC on polyimide are dependent on their hierarchical surface nanostructure which ranges from isotropic nanoporous morphology to fibrous morphology. Results also show that increasing gap sizes lead to an increase in contact angles and thus an increase in the hydrophobicity of the surface. Hence, our work highlight the potential of this approach for manufacturing flexible devices with tailored surfaces.

scholarly journals Structural patterns at all scales in a nonmetallic chiral Au133(SR)52 nanoparticle

2015 ◽  
Vol 1 (2) ◽  
pp. e1500045 ◽  
Author(s):  
Chenjie Zeng ◽  
Yuxiang Chen ◽  
Kristin Kirschbaum ◽  
Kannatassen Appavoo ◽  
Matthew Y. Sfeir ◽  
...  
Keyword(s):  
Surface Characterization ◽  
Gold Atom ◽  
Complex Surface ◽  
Metal Core ◽  
Structural Ordering ◽  
X Ray Crystallography ◽  
Thiolate Ligands ◽  
Pattern Structures ◽  
Surface Patterns ◽  
Conceptual Advance

Structural ordering is widely present in molecules and materials. However, the organization of molecules on the curved surface of nanoparticles is still the least understood owing to the major limitations of the current surface characterization tools. By the merits of x-ray crystallography, we reveal the structural ordering at all scales in a super robust 133–gold atom nanoparticle protected by 52 thiolate ligands, which is manifested in self-assembled hierarchical patterns starting from the metal core to the interfacial –S–Au–S– ladder-like helical “stripes” and further to the “swirls” of carbon tails. These complex surface patterns have not been observed in the smaller nanoparticles. We further demonstrate that the Au133(SR)52 nanoparticle exhibits nonmetallic features in optical and electron dynamics measurements. Our work uncovers the elegant self-organization strategies in assembling a highly robust nanoparticle and provides a conceptual advance in scientific understanding of pattern structures.

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