scholarly journals UV-LED as a New Emerging Tool for Curable Polyurethane Acrylate Hydrophobic Coating

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 487
Author(s):  
Siti Khairunisah Ghazali ◽  
Nadia Adrus ◽  
Rohah A. Majid ◽  
Fathilah Ali ◽  
Jamarosliza Jamaluddin
Keyword(s):  
Light Emitting Diode ◽  
Urethane Acrylate ◽  
Water Contact ◽  
Promising Alternative ◽  
Light Emitting ◽  
Hydrophobic Coatings ◽  
Hydrophobic Coating ◽  
Uv Led ◽  
A New Technique ◽  
High Degree

The elimination of mercury, low energy consumption, and low heat make the ultraviolet light-emitting diode (UV-LED) system emerge as a promising alternative to conventional UV-mercury radiation coating. Hence, a series of hydrophobic coatings based on urethane acrylate oligomer and fluorinated monomer via UV-LED photopolymerisation was designed in this paper. The presence of fluorine component at 1160 cm−1, 1235 cm−1, and 1296 cm−1 was confirmed by Fourier Transform Infra-Red spectroscopy. A considerably high degree C=C conversion (96–98%) and gel fraction (95–93%) verified the application of UV-LED as a new technique in radiation coating. It is well-accepted that fluorinated monomer can change the surface wettability as the water contact angle of the coating evolved from 88.4° to 121.2°, which, in turn, reduced its surface free energy by 70.5%. Hence, the hydrophobicity of the coating was governed by the migration of the fluorine component to the coating surface as validated by scanning electron and atomic force microscopies. However, above 4 phr of fluorinated monomer, the transparency of the cured coating examined by UV-visible spectroscopy experienced approximately a 16% reduction. In summary, the utilisation of UV-LED was a great initiative to develop green aspect in photopolymerisation, particularly in coating technology.

Comparison of continuous versus pulsed ultraviolet light emitting diode use for the inactivation of Bacillus globigii spores

2014 ◽  
Vol 70 (9) ◽  
pp. 1473-1480 ◽  
Author(s):  
Tho Tran ◽  
LeeAnn Racz ◽  
Michael R. Grimaila ◽  
Michael Miller ◽  
Willie F. Harper
Keyword(s):  
Light Emitting Diode ◽  
High Energy ◽  
Cellular Damage ◽  
Operating Life ◽  
Promising Alternative ◽  
Light Emitting ◽  
Uv Led ◽  
Pulsed Ultraviolet Light ◽  
Uv Lamps ◽  
Uv Range

Light emitting diodes (LEDs) in the ultraviolet (UV) range offer a promising alternative for the disinfection of water. LEDs have many advantages over conventional UV lamps but there are concerns related to the operating life of the LED lamps. In this project Bacillus globigii was inactivated using UV LED technology. The experimental strategy included using pulsed ultraviolet (PUV) output rather than continuous UV (CUV) current in order to reduce the power requirements and extend the life of the lamps. The kinetic profiles for CUV experiments reached 6-log inactivation faster than PUV at 9.1% duty cycle (approx. 840 vs. 5,000 s) but the PUV required lower fluence (365 vs. 665 J/m2). In addition, the inactivation rate constants associated with PUV were generally higher than those of CUV (4.6–5.1 vs. 3.6–4.4 m2/J), which supports the notion that high energy bursts are more effective at causing cellular damage. Multi-target kinetics applied to most of the kinetic observations and tailing effects were generally observed. PUV LED appears to have potential to extend the lifetime of the LEDs for inactivation of spore-forming pathogens.

scholarly journals Design of a Secondary Freeform Lens of UV LED Mosquito-Trapping Lamp for Enhancing Trapping Efficiency

Crystals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 335 ◽  
Author(s):  
Wei-Hsiung Tseng ◽  
Diana Juan ◽  
Wei-Cheng Hsiao ◽  
Cheng-Han Chan ◽  
Hsin-Yi Ma ◽  
...  
Keyword(s):  
Light Intensity ◽  
Intensity Distribution ◽  
Light Emitting Diode ◽  
Trapping Efficiency ◽  
Axially Symmetric ◽  
Light Intensity Distribution ◽  
Light Emitting ◽  
Led Light ◽  
Uv Led ◽  
Freeform Lens

In this study, our proposed ultraviolet light-emitting diode (UV LED) mosquito-trapping lamp is designed to control diseases brought by insects such as mosquitoes. In order to enable the device to efficiently catch mosquitoes in a wider area, a secondary freeform lens (SFL) is designed for UV LED. The lens is mounted on a 3 W UV LED light bar as a mosquito-trapping lamp of the new UV LED light bar module to achieve axially symmetric light intensity distribution. The special SFL is used to enhance the trapping capabilities of the mosquito-trapping lamp. The results show that when the secondary freeform surface lens is applied to the experimental outdoor UV LED mosquito-trapping lamp, the trapping range can be expanded to 100π·m2 and the captured mosquitoes increased by about 300%.

scholarly journals In Vitro Effect of Photodynamic Therapy with Different Lights and Combined or Uncombined with Chlorhexidine on Candida spp.

Pharmaceutics ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1176
Author(s):  
Vanesa Pérez-Laguna ◽  
Yolanda Barrena-López ◽  
Yolanda Gilaberte ◽  
Antonio Rezusta
Keyword(s):  
Photodynamic Therapy ◽  
Light Emitting Diode ◽  
Antimicrobial Effect ◽  
Photodynamic Treatment ◽  
Candida Spp ◽  
Promising Alternative ◽  
Light Emitting ◽  
Colony Forming Units ◽  
Vitro Effect

Candidiasis is very common and complicated to treat in some cases due to increased resistance to antifungals. Antimicrobial photodynamic therapy (aPDT) is a promising alternative treatment. It is based on the principle that light of a specific wavelength activates a photosensitizer molecule resulting in the generation of reactive oxygen species that are able to kill pathogens. The aim here is the in vitro photoinactivation of three strains of Candida spp., Candida albicans ATCC 10231, Candida parapsilosis ATCC 22019 and Candida krusei ATCC 6258, using aPDT with different sources of irradiation and the photosensitizer methylene blue (MB), alone or in combination with chlorhexidine (CHX). Irradiation was carried out at a fluence of 18 J/cm2 with a light-emitting diode (LED) lamp emitting in red (625 nm) or a white metal halide lamp (WMH) that emits at broad-spectrum white light (420–700 nm). After the photodynamic treatment, the antimicrobial effect is evaluated by counting colony forming units (CFU). MB-aPDT produces a 6 log10 reduction in the number of CFU/100 μL of Candida spp., and the combination with CHX enhances the effect of photoinactivation (effect achieved with lower concentration of MB). Both lamps have similar efficiencies, but the WMH lamp is slightly more efficient. This work opens the doors to a possible clinical application of the combination for resistant or persistent forms of Candida infections.

Miniaturized UV-LED Array Chip Photochemical Vapor Generator Coupled with Point Discharge Optical Emission Spectrometer for Determination of Trace Selenium

2021 ◽  
Author(s):  
Mengtian Li ◽  
Yi Luo ◽  
Zhirong Zou ◽  
Fujian Xu ◽  
Xiaoming Jiang ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Optical Emission ◽  
Nano Tio2 ◽  
Light Emitting ◽  
Uv Led ◽  
Led Array ◽  
Point Discharge ◽  
Photochemical Vapor Generation ◽  
Optical Emission Spectrometer

An ultraviolet light emitting diode (UV-LED) array chip as irradiation source for nano-TiO2 catalyzed photochemical vapor generation (PCVG) was combined with a hollow electrode point discharge microplasma optical emission spectrometer...

Ultraviolet light-emitting diode (UV LED) trap the West Indian sweet potato weevil, Euscepes postfasciatus (Coleoptera: Curculionidae)

2012 ◽  
Vol 47 (3) ◽  
pp. 285-290 ◽  
Author(s):  
Masako Katsuki ◽  
Yusuke Omae ◽  
Kensuke Okada ◽  
Toru Kamura ◽  
Takashi Matsuyama ◽  
...  
Keyword(s):  
Sweet Potato ◽  
Ultraviolet Light ◽  
Light Emitting Diode ◽  
West Indian ◽  
The West ◽  
Light Emitting ◽  
Uv Led ◽  
Sweet Potato Weevil ◽  
Euscepes Postfasciatus

scholarly journals 3D Microlithography Using an Integrated System of 5-mm UV-LEDs with a Tilt-Rotational Sample Holder

Micromachines ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 157 ◽  
Author(s):  
Sabera Fahmida Shiba ◽  
Hyeongmin Jeon ◽  
Jong-Soo Kim ◽  
Jong-Eun Kim ◽  
Jungkwun Kim
Keyword(s):  
Light Source ◽  
Light Emitting Diode ◽  
Vertical Direction ◽  
Ultra Violet ◽  
Integrated System ◽  
Sample Holder ◽  
Large Area ◽  
Light Emitting ◽  
Uv Led ◽  
Uv Leds

This paper demonstrates a 3D microlithography system where an array of 5 mm Ultra Violet-Light Emitting Diode (UV-LED) acts as a light source. The unit of the light source is a UV-LED, which comes with a length of about 8.9 mm and a diameter of 5 mm. The whole light source comprises 20 × 20 matrix of such 5 mm UV-LEDs giving a total number of 400 LEDs which makes it a very favorable source with a large area for having a batch production of the desired microstructures. This light source is able to give a level of precision in microfabrication which cannot be obtained using commercial 3D printers. The whole light source performs continuous rotational movement once it is turned on. This can also move up and down in a vertical direction. This multidirectional light source also comprises a multidirectional sample holder. The light source teaming up with the multidirectional sample holder highly facilitates the process of fabrication of a huge range of 3D structures. This article also describes the different levels of characterization of the system and demonstrates several fabricated 3D microstructures including high aspect ratio vertical micro towers, twisted turbine structures, triangles, inclined pillar ‘V’ structures, and hollow horn structures as well.

Fabrication and antimicrobial effects of silver nanoparticle-poly(N-isopropylacrylamide)-poly(ferrocenylsilane) hydrogel composites

2012 ◽  
Vol 1453 ◽  
Author(s):  
Xiaofeng Sui ◽  
Xueling Feng ◽  
Andrea Di Luca ◽  
Clemens A. van Blitterswijk ◽  
Lorenzo Moroni ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Light Emitting ◽  
Uv Led ◽  
Hydrogel Network ◽  
Redox Responsive ◽  
Equilibrium Swelling ◽  
Hydrogel Composites ◽  
Equilibrium Swelling Ratio ◽  
Strong Antimicrobial Activity

ABSTRACTNovel hydrogels composed of thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) and redox-responsive poly(ferrocenylsilane) (PFS) macromolecules were formed by photopolymerization. PFS chains bearing acrylate side groups were copolymerized with NIPAM and N,N’-methylenebisacrylamide in tetrahydrofuran in a predetermined ratio under ultraviolet light-emitting diode (UV-LED) irradiation at a wavelength of 365 nm, in the presence of a photoinitiator. Crosslinking occurred smoothly, providing homogeneous hydrogels. The equilibrium swelling ratio, rheology and morphology of these hybrid PNIPAM-PFS-based hydrogels were investigated. In-situ fabrication of silver nanoparticles inside the hydrogel network via reduction of silver nitrate by the PFS chains led to hydrogel composites. These composites showed strong antimicrobial activity while maintaining a high biocompatibility with cells.

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