scholarly journals Preparation and Properties of Cyanobacteria-Based Carbon Quantum Dots/Polyvinyl Alcohol/ Nanocellulose Composite

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1143 ◽  
Author(s):  
Li Xu ◽  
Ying Li ◽  
Shiyu Gao ◽  
Yue Niu ◽  
Huaxuan Liu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Polyvinyl Alcohol ◽  
Water Resistance ◽  
Composite Films ◽  
Barrier Properties ◽  
Carbon Quantum Dots ◽  
Infrared Light ◽  
Quantum Yields ◽  
Hydroxyl Groups ◽  
Light Barrier

Blue luminescent carbon quantum dots (CQDs) were prepared from cyanobacteria by a hydrothermal method. The PL quantum yields of the obtained CQDs was 5.30%. Cyanobacteria-based carbon quantum dots/polyvinyl alcohol/nanocellulose composite films were prepared, which could emit bright blue under UV light. FTIR characterization showed that the composite films had hydroxyl groups on the surface and no new groups were formed after combining the three materials. The photoluminescence (PL) spectra revealed that the emission of the prepared CQDs was excitation dependent. Studies on the water resistance performance and light barrier properties of the composite films showed that they possessed higher water resistance properties and better UV/infrared light barrier properties. Therefore, we report the cyanobacteria-based carbon quantum dots/polyvinyl alcohol/nanocellulose composite films have the potential to be applied in flexible packaging materials, anti-fake materials, UV/infrared light barrier materials and so on.

Carbon quantum dots incorporated keratin/polyvinyl alcohol hydrogels: Preparation and photoluminescent assessment

2017 ◽  
Vol 207 ◽  
pp. 57-61 ◽  
Author(s):  
Chohye Lee ◽  
Bishweshwar Pant ◽  
Byoung-Suhk Kim ◽  
Rae-Sang Jang ◽  
Seungil Park ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Polyvinyl Alcohol ◽  
Carbon Quantum Dots

Near-infrared light triggered photo-therapy, in combination with chemotherapy using magnetofluorescent carbon quantum dots for effective cancer treating

Carbon ◽  
2017 ◽  
Vol 118 ◽  
pp. 752-764 ◽  
Author(s):  
Ming Zhang ◽  
Wentao Wang ◽  
Ninglin Zhou ◽  
Ping Yuan ◽  
Yutian Su ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Near Infrared ◽  
Carbon Quantum Dots ◽  
Infrared Light ◽  
Near Infrared Light

scholarly journals Improving Thermal, Mechanical, and Barrier Properties of Feather Keratin/Polyvinyl Alcohol/Tris(hydroxymethyl)aminomethane Nanocomposite Films by Incorporating Sodium Montmorillonite and TiO2

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 298 ◽  
Author(s):  
Shufang Wu ◽  
Xunjun Chen ◽  
Minghao Yi ◽  
Jianfang Ge ◽  
Guoqiang Yin ◽  
...  
Keyword(s):  
Polyvinyl Alcohol ◽  
Three Dimensional ◽  
Water Vapor Permeability ◽  
Barrier Properties ◽  
Nanocomposite Films ◽  
Light Transmittance ◽  
Vapor Permeability ◽  
Hydroxyl Groups ◽  
Sodium Montmorillonite ◽  
Feather Keratin

In this study, feather keratin/polyvinyl alcohol/tris(hydroxymethyl)aminomethane (FK/PVA/Tris) bionanocomposite films containing two types of nanoparticles, namely one-dimensional sodium montmorillonite (MMT) clay platelets (0.5, 1, 3, and 5 wt%) and three-dimensional TiO2 nanospheres (0.5, 1, 3, and 5 wt%), are prepared using solvent casting method. X-ray diffraction studies confirm the completely exfoliated structure of FK/PVA/Tris/MMT nanocomposites. The successful formation of new hydrogen bonds between the hydroxyl groups of the film matrix and the nanofillers is confirmed by Fourier transform infrared spectroscopy. The tensile strength, elongation at break, and initial degradation temperature of the films are enhanced after MMT and TiO2 incorporation. The water vapor permeability, oxygen permeability, and light transmittance decrease with increase in TiO2 and MMT contents. In summary, nanoblending is an effective method to promote the application of FK/PVA/Tris blend films in the packaging field.

scholarly journals A turn-on fluorescent sensor based on coffee-grounds carbon dots for the detection of sodium cyclamate

2021 ◽  
Author(s):  
Junzhe Chen ◽  
Haiying Du ◽  
Yifeng Xu ◽  
Boyu Ma ◽  
Zhihong Zheng ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Quantum Dots ◽  
Shell Structure ◽  
Sulfamic Acid ◽  
Carbon Quantum Dots ◽  
Core Shell ◽  
Hydroxyl Groups ◽  
Coffee Grounds ◽  
Core Shell Structure ◽  
Sodium Cyclamate

Abstract Carbon quantum dots (CQDs) were synthesized by coffee-grounds as carbon source under hydrothermal carbonization treatment for the first time. The obtained CQDs showed a strong emission at the wavelength of 460 nm, with an optimum excitation of 370 nm, and enrichment of the surface functional groups(-OH, -NH2). Sodium cyclamate in an aqueous solution and the CQDs could form a core-shell structure by hydrogen-bonding and van der waals bonding to enhance the fluorescent emission. Cyclohexyl sulfamate forms cyclohexyl sulfamate in an aqueous solution and then undergoes dehydration and condensation with the hydroxyl groups on the carbon quantum dots, and finally sodium cyclamate forms a core-shell structure around the carbon quantum dots.环己基氨基磺酸盐在水溶液中形成环己基氨基磺酸盐，然后与碳量子点上的羟基进行脱水和缩合，最后环甜酸钠在碳量子点周围形成核-壳结构。Cyclohexyl sulfamate form a cyclohexyl sulfamic acid in an aqueous solution followed by dehydration condensation with hydroxyl groups on the carbon quantum dots, cyclamate final core-shell structure is formed in the peripheral carbon quantum dot,

scholarly journals Rapid Synthesis of highly luminescent Carbon Quantum Dots using Low-Pressurized Microwave Solvothermal Heating

2019 ◽  
Author(s):  
Kenta Hagiwara ◽  
Satoshi Horikoshi
Keyword(s):  
Quantum Dots ◽  
Carbon Quantum Dots ◽  
Synthetic Methods ◽  
Quantum Yields ◽  
Protective Agent ◽  
The Novel ◽  
Microwave Chemistry ◽  
High Quantum ◽  
Surface Modified ◽  
The Relationship

Since the first serendipity of carbon quantum dots (CQDs)1, it is expected to be used for imaging materials for reusable living bodies (e.g. Hela cells). However, the reported CQDs synthetic methods have yet to be at the practical levels; the quantum yields is low, and synthetic condition is over 5 hrs under more than 30 atms. In this research, we ameliorated the problems of CQDs synthesis and luminescence (quantum yields) by the novel synthesis protocol using microwave chemistry. Specifically, we synthesized high quantum yields CQDs (61%) by utilizing a microwave chemical synthesis, synthesizing at low pressure condition (lower than 5 atom) and short reaction time (3 hrs). The achievement of this high quantum yields made it clear that the contribution of polyethylene glycol (PEG) shell to CQDs is large. It was confirmed from the DLS and TEM image that the particle size of the synthesized particles was 8 to 13 nm (Fig. 1). On the other hand, the relationship between the polymerization degree of added PEG and the quantum yields to the addition amount is summarized in Table 1. The quantum yields of CQDs without addition of PEG was 16.7 %, while it was improved at 61.1 % when 0.6 g of PEG6000 (Molecular weight: 6000) was added.We succeeded in remarkably improving the quantum yields by using PEG, which is usually used as a protective agent, as a shell. By using this method, we succeeded in improving the quantum yields of the existing report by approximately 3 times. From the surface modified structure of PEG, the mechanism of improvement of quantum yields will be considered.[1] X. Xu et al., J. Am. Chem. Soc., 2004, 126, 12736–12737. 

scholarly journals Preparation and Performance of Radiata-Pine-Derived Polyvinyl Alcohol/Carbon Quantum Dots Fluorescent Films

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 67 ◽  
Author(s):  
Li Xu ◽  
Yushu Zhang ◽  
Haiqing Pan ◽  
Nan Xu ◽  
Changtong Mei ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Water Resistance ◽  
Cellulose Nanofibers ◽  
Tensile Modulus ◽  
Radiata Pine ◽  
Carbon Quantum Dots ◽  
Nanocomposite Films ◽  
Excitation Wavelength ◽  
Nano Materials ◽  
Nano Composite

In this study, the low-cost processing residue of Radiata pine (Pinus radiata D. Don) was used as the lone carbon source for synthesis of CQDs (Carbon quantum dots) with a QY (The quantum yield of the CQDs) of 1.60%. The CQDs were obtained by the hydrothermal method, and +a PVA-based biofilm was prepared by the fluidized drying method. The effects of CQDs and CNF (cellulose nanofibers) content on the morphology, optical, mechanical, water-resistance, and wettability properties of the PVA/CQDs and PVA/CNF/CQDs films are discussed. The results revealed that, when the excitation wavelength was increased from 340 to 390 nm, the emission peak became slightly red-shifted, which was induced by the condensation between CQDs and PVA. The PVA composite films showed an increase in fluorescence intensity with the addition of the CNF and CQDs to polymers. The chemical structure of prepared films was determined by the FTIR spectroscopy, and no new chemical bonds were formed. In addition, the UV transmittance was inversely proportional to the change of CQDs content, which indicated that CQDs improved the UV barrier properties of the films. Furthermore, embedding CQDs Nano-materials and CNF into the PVA matrix improved the mechanical behavior of the Nano-composite. Tensile modulus and strength at break increased significantly with increasing the concentration of CQDs Nano-materials inside the Nano-composite, which was due to the increased in the density of crosslinking behavior. With the increase of CQDs content (>1 mL), the water absorption and surface contact angle of the prepared films decreased gradually, and the water-resistance and surface wettability of the films were improved. Therefore, PVA/CNF/CQDs bio-nanocomposite films could be used to prepare anti-counterfeiting, high-transparency, and ultraviolet-resistant composites, which have potential applications in ecological packaging materials.

Sign in / Sign up

Export Citation Format

Share Document