scholarly journals Humidity-Responsive Photonic Films and Coatings Based on Tuned Cellulose Nanocrystals/Glycerol/Polyethylene Glycol

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3695
Author(s):  
Amin Babaei-Ghazvini ◽  
Bishnu Acharya
Keyword(s):  
Polyethylene Glycol ◽  
Water Uptake ◽  
Cellulose Nanocrystals ◽  
Color Change ◽  
Colloidal Suspensions ◽  
Mechanical Tests ◽  
Humidity Sensors ◽  
Water Contact ◽  
Structural Colors ◽  
Mesoporous Film

It has been extensively reported that cellulose nanocrystals (CNCs) can represent structural colors due to their unique chiral-nematic self-assembly. However, the application of this remarkable structure does need further investigation. It has been challenging to keep the selective reflection band (SRB) resulting from the CNC structure in the visible spectrum. Herein, composition of CNC colloidal suspensions with polyethylene glycol (PEG) and glycerol (Gly) have been studied to develop humidity-responsive sensors in the form of coatings and films. The fabricated samples were characterized for their mechanical properties, optical properties, water uptake capacity, water contact angle, and surface roughness. Additionally, the chemical structure of the samples was studied with FTIR spectroscopy. The produced humidity indicators on microbial glass slides were maintained and tested in a different relative humidity range from 20% to 98% with a different color response from blue to red, respectively. The color change of the humidity sensors was reversible for several cycles. It should be noted that the color change can be detected easily by the naked eye. The water uptake test showed that pure CNC and CNC/Gly had the lowest (34%) and highest (83%) water absorption levels. The mechanical tests for CNC/PEG composites showed the highest tensile strength (40.22 MPa). Moreover, microstructural characterizations confirmed the CNC pitch formation in all the samples. Addition of the fillers increased the CNC pitch, resulting in a mesoporous film formation. These produced humidity sensors are promising candidates in food and drug packaging due to their biodegradability, biocompatibility, and cost-effectiveness.

scholarly journals Electrospun 5-chloro-8-hydroxyquinoline-Loaded Cellulose Acetate/Polyethylene Glycol Antifungal Membranes Against Esca

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1617 ◽  
Author(s):  
Spasova ◽  
Manolova ◽  
Rashkov ◽  
Naydenov
Keyword(s):  
Polyethylene Glycol ◽  
Cellulose Acetate ◽  
Plant Protection ◽  
Bioactive Compound ◽  
Mechanical Tests ◽  
Fibrous Materials ◽  
Water Contact ◽  
Phaeomoniella Chlamydospora ◽  
Optical And Mechanical Properties ◽  
Surface Morphologies

Esca is one of the earliest described diseases in grapevines and causes trunk damage and the sudden wilting of the entire plant; it is caused mainly by the species Phaeomoniella chlamydospora (P. chlamydospora) and Phaeoacremonium aleophilum (P. aleophilum). In practice, there are no known curative approaches for fighting esca directly, which is a huge problem for preserving vineyards. Micro- and nanofibrous membranes from cellulose acetate (CA) and cellulose acetate/polyethylene glycol (CA/PEG) containing 5-chloro-8-hydroxyquinolinol (5-Cl8Q) were successfully prepared by electrospinning. The surface morphologies and optical and mechanical properties of the membranes were characterized by using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Vis), water contact angle measurements and mechanical tests. It was found that the bioactive compound release was facilitated by PEG. The antifungal activities of the obtained materials against P. chlamydospora and P. aleophilum were studied. We have demonstrated that 5-Cl8Q is an efficient and sustainable antifungal agent against P. chlamydospora and P. aleophilum. Moreover, for the first time, the present study reveals the possibility of using electrospun polymer membranes containing 5-Cl8Q which impede the penetration and growth of P. chlamydospora and P. aleophilum. Thus, the obtained fibrous materials can be suitable candidates for plant protection against diverse fungi.

Assessment of Color Stability of Treated Leathers with Silicone Oil and Polyethylene Glycol

2014 ◽  
Vol 1 (1) ◽  
pp. 24-34
Author(s):  
Alireza K. ◽  
Hossein Ahmadi ◽  
Mohsen Mohammadi
Keyword(s):  
Ascorbic Acid ◽  
Polyethylene Glycol ◽  
Treatment Process ◽  
Color Change ◽  
Silicone Oil ◽  
Accelerated Aging ◽  
Color Stability ◽  
Antioxidant Additive ◽  
Before And After ◽  
Aesthetic Values

Lubricants and leather dressings are the most common treatments of dry and water logged historical leathers. Color change has a great importance during the time and treatment process, due to visual and aesthetic values of historic leather relics. Polyethylene glycol (PEG) and silicone oil (SiO) are frequently used leather dressings in the conservation procedures. Therefore, color stability of treated leathers with PEG and SiO were investigated before and after heat accelerated aging. Moreover, application of ascorbic acid was evaluated as an antioxidant additive for PEG (PEG+AA).Color change after treatment and aging were studied by colorimetry technique in the CIE *L*a*b system. Results indicated to severe color alteration in PEG treated and aged leathers with or without ascorbic acid. Whereas, SiO treated samples showed better stability and minimum color shift after aging. Silicone oil was characterized as the best dressing for historical leathers with compared to PEG and PEG+AA, due to its high stability and aesthetical properties.

scholarly journals Investigation of the selective color-changing mechanism of Dynastes tityus beetle (Coleoptera: Scarabaeidae)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiyu Sun ◽  
Wei Wu ◽  
Limei Tian ◽  
Wei Li ◽  
Fang Zhang ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Color Change ◽  
Incidence Angle ◽  
Ion Beam ◽  
Three Dimensional ◽  
Water Infiltration ◽  
Photonic Materials ◽  
Local Color ◽  
Water Contact ◽  
Color Changes

AbstractNot only does the Dynastes tityus beetle display a reversible color change controlled by differences in humidity, but also, the elytron scale can change color from yellow-green to deep-brown in specified shapes. The results obtained by focused ion beam-scanning electron microscopy (FIB-SEM), show that the epicuticle (EPI) is a permeable layer, and the exocuticle (EXO) is a three-dimensional photonic crystal. To investigate the mechanism of the reversible color change, experiments were conducted to determine the water contact angle, surface chemical composition, and optical reflectance, and the reflective spectrum was simulated. The water on the surface began to permeate into the elytron via the surface elemental composition and channels in the EPI. A structural unit (SU) in the EXO allows local color changes in varied shapes. The reflectance of both yellow-green and deep-brown elytra increases as the incidence angle increases from 0° to 60°. The microstructure and changes in the refractive index are the main factors that influence the process of reversible color change. According to the simulation, the lower reflectance causing the color change to deep-brown results from water infiltration, which increases light absorption. Meanwhile, the waxy layer has no effect on the reflection of light. This study lays the foundation to manufacture engineered photonic materials that undergo controllable changes in iridescent color.

scholarly journals Cellulose Acetate-Based Electrospun Materials with a Variety of Biological Potentials: Antibacterial, Antifungal and Anticancer

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1631
Author(s):  
Mariya Spasova ◽  
Nevena Manolova ◽  
Iliya Rashkov ◽  
Petya Tsekova ◽  
Ani Georgieva ◽  
...  
Keyword(s):  
Cellulose Acetate ◽  
Mechanical Tests ◽  
Fibrous Materials ◽  
Water Contact ◽  
Antibacterial And Antifungal Activities ◽  
3T3 Fibroblasts ◽  
Angle Measurements ◽  
Zones Of Inhibition ◽  
Model Drug ◽  
Antibacterial And Antifungal

Novel eco-friendly fibrous materials with complex activities from cellulose acetate and cellulose acetate/polyethylene glycol (CA,PEG) containing 5-chloro-8-hydroxyquinoline as a model drug were obtained by electrospinning. Several methods, including scanning electron microscopy, X-ray diffraction analysis, ultraviolet-visible spectroscopy, water contact angle measurements, and mechanical tests, were utilized to characterize the obtained materials. The incorporation of PEG into the fibers facilitated the drug release. The amounts of the released drug from CA/5-Cl8Q and CA,PEG/5-Cl8Q were 78 ± 3.38% and 86 ± 3.02%, respectively (for 175 min). The antibacterial and antifungal activities of the obtained materials were studied. The measured zones of inhibition of CA/5-Cl8Q and CA,PEG/5-Cl8Q mats were 4.0 ± 0.18 and 4.5 ± 0.2 cm against S. aureus and around 4.0 ± 0.15 and 4.1 ± 0.22 cm against E. coli, respectively. The complete inhibition of the C. albicans growth was detected. The cytotoxicity of the obtained mats was tested toward HeLa cancer cells, SH-4 melanoma skin cells, and mouse BALB/c 3T3 fibroblasts as well. The CA/5-Cl8Q and CA,PEG/5-Cl8Q materials exhibited anticancer activity and low normal cell toxicity. Thus, the obtained fibrous materials can be suitable candidates for wound dressing applications and for application in local cancer treatment.

The effect of chemical treatment methods on the outdoor performance of waste textile fiber-reinforced polymer composites

2016 ◽  
Vol 51 (14) ◽  
pp. 2009-2021 ◽  
Author(s):  
Mustafa Bakkal ◽  
M Safa Bodur ◽  
H Ece Sonmez ◽  
B Can Ekim
Keyword(s):  
Polymer Composites ◽  
Water Uptake ◽  
Color Change ◽  
Fiber Reinforced Polymer ◽  
Silane Treatment ◽  
Textile Fiber ◽  
Fiber Reinforced ◽  
Chemical Treatments ◽  
Reinforced Polymer ◽  
Fiber Reinforced Polymer Composites

In this study, weathering effect on untreated textile fiber-reinforced polymer composites and the effect of different chemical treatments for better interfacial adhesion on the outdoor performance were investigated. Degradation of physical, mechanical, and chemical properties of textile fiber-reinforced polymer composites was evaluated through common chemical treatments such as maleated coupling, alkaline treatment, silane treatment, and alkali–silane treatment. Untreated and chemically treated textile fiber-reinforced polymer composites were subjected to water uptake and UV exposure up to 1000 h. Tensile and impact properties were mechanically examined, and the changes on the physical properties due to water uptake, swelling, and color change were investigated. In addition, Fourier transform infrared spectrum analysis was performed in order to evaluate the chemical changes after exposure.

scholarly journals PLA-Based Hybrid and Composite Electrospun Fibrous Scaffolds as Potential Materials for Tissue Engineering

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Anna Magiera ◽  
Jarosław Markowski ◽  
Elzbieta Menaszek ◽  
Jan Pilch ◽  
Stanislaw Blazewicz
Keyword(s):  
Tissue Engineering ◽  
Mechanical Tests ◽  
Hybrid Structures ◽  
Poly Lactic Acid ◽  
Electrospinning Technique ◽  
Water Contact ◽  
Human Osteoblasts ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Normal Human

The aim of the study was to manufacture poly(lactic acid)- (PLA-) based nanofibrous nonwovens that were modified using two types of modifiers, namely, gelatin- (GEL-) based nanofibres and carbon nanotubes (CNT). Hybrid nonwovens consisting of PLA and GEL nanofibres (PLA/GEL), as well as CNT-modified PLA nanofibres with GEL nanofibres (PLA + CNT/GEL), in the form of mats, were manufactured using concurrent-electrospinning technique (co-ES). The ability of such hybrid structures as potential scaffolds for tissue engineering was studied. Both types of hybrid samples and one-component PLA and CNTs-modified PLA mats were investigated using scanning electron microscopy (SEM), water contact angle measurements, and biological and mechanical tests. The morphology, microstructure, and selected properties of the materials were analyzed. Biocompatibility and bioactivity in contact with normal human osteoblasts (NHOst) were studied. The coelectrospun PLA and GEL nanofibres retained their structures in hybrid samples. Both types of hybrid nonwovens were not cytotoxic and showed better osteoinductivity in comparison to scaffolds made from pure PLA. These samples also showed significantly reduced hydrophobicity compared to one-component PLA nonwovens. The CNT-contained PLA nanofibres improved mechanical properties of hybrid samples and such a 3D system appears to be interesting for potential application as a tissue engineering scaffold.

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 HYDROPHOBIC IMPREGNATION OF GEOPOLYMER COMPOSITE BY ETHOXYSILANES

2018 ◽  
Vol 58 (3) ◽  
pp. 184
Author(s):  
Zdeněk Mašek ◽  
Linda Diblikova
Keyword(s):  
Contact Angle ◽  
Elevated Temperature ◽  
Water Contact Angle ◽  
Water Uptake ◽  
Outer Surface ◽  
Alkyl Group ◽  
Sio2 Nanoparticles ◽  
Water Contact ◽  
Composite Surface ◽  
Geopolymer Composites

A geopolymer composite was impregnated by incorporating the hydrophobic alkyl group on the outer surface and in the inner structure of the geopolymer. Ethoxysilanes 1H,1H,2H,2H perfluoroctyltriethoxysilane and hexadecyltrimethoxysilane were used as the source of hydrophobic groups. Three types of solutions based on the ethoxysilanes were prepared according to adapted procedures. The modification of the geopolymer composites was done by their immersion into the hydrophobic solutions followed by drying at a laboratory or elevated temperature. The effectivity of the procedure was evaluated by measuring the water contact angle on the surface of the modified composite and by measuring the water uptake and stiffness of the composite. The results confirmed that the silanes hydrolyzed in sol containing SiO2 nanoparticles have a higher hydrophobization effect than solutions of simply hydrolyzed silanes. The resulting impregnation procedure led to the change of the geopolymer composite surface from hydrophilic to hydrophobic.

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