Laser ablation

Dowding, Colin

doi:10.1533/9781845699819.7.575

Cited by 14 publications

(11 citation statements)

References 70 publications

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“…The second stage (P/U = 0.18-0.4) revealed an increase in HAZ with increasing P/U with high fluctuations for HAZ values at the same P/U ratio as a result of including the laser processing at speeds of 12, 15, and 17 mm/s. Whilst the third stage (P/U = 0.4-0.84) showed a significant increase in HAZ with increasing P/U at a lower rate compared with its corresponding in the first Undoubtedly, widening HAZ with increasing the input power and decreasing the scanning speed throughout the micromachining can be explained based on increasing the temperature of the fusion zone with the accumulation of the heat laterally along the ablation zone leading to high thermal stress [35]. As a result, cracks and distortions can occur due to the expansion and contraction of the polymer melt during the ablation process.…”

Section: Heat-affected Zone (Haz)mentioning

confidence: 93%

“…The decrease of surface roughness with increasing the input power and decreasing the scanning speed throughout the micromachining can be explained based on increasing the temperature that accelerates the kinetics of melting and vaporization processes with minimization of the plume etching resulting from plume confinement with a pulsed laser beam at fluences over the ablation threshold [35]. This can also be the likely reason for the significant decrease in the surface roughness during micromachining at a moving speed of 15 mm/s.…”

Section: Microchannel Roughnessmentioning

confidence: 99%

“…Thus, squeezing the molten polymer layer out of the groove to form the bulges will become more difficult. Nevertheless, the higher temperature gradient in the fusion zone can lead to extrusion of the softened polymer materials near the ablation pool, forming the bulges [35]. Furthermore, the thermal state of the epoxy Fig.…”

Section: Bulge Heightmentioning

confidence: 99%

“…14 Micrographs of epoxy resin machined using CO 2 laser at varying laser powers and scanning speeds extremely low thermal conductivity κ = 0.2 W/(m*K) [36]. The low thermal conductivity (high thermal resistances) leads to good heat dissipation and subsequently steep thermal gradients and low thermal stress resulting in asymmetric heat-affected zones (HAZ) during ablation trials [34,35]. In this context, the HAZ geometry may be affected by the microchannel dimensions and the cooling time [34].…”

Section: Heat-affected Zone (Haz)mentioning

confidence: 99%

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Development of epoxy resin-based microfluidic devices using CO2 laser ablation for DNA amplification point-of-care (POC) applications

Mansour

Soliman

El-Bab

et al. 2022

Int J Adv Manuf Technol

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Microfluidic devices are a rising technology to automatize chemical and biological operations. In this context, laser ablation has significant potential for polymer-based microfluidic platforms’ fast and economical manufacturing. Nevertheless, the manufacturing of epoxy-based microfluidic chips is considered highly cost full due to the demand for cleanroom facilities that utilize expensive equipment and lengthy processes. Therefore, this study targeted investigating the feasibility of epoxy resins to be fabricated as a lab-on-chip using carbon dioxide laser ablation. The chemical structural properties and thermal stability of the plain epoxy resins were characterized by Fourier transform infrared spectral analysis (FT-IR) and thermogravimetric analysis (TGA). Moreover, a specific migration test was performed to quantify potential migrants by gas chromatography coupled to mass spectrometry (GC–MS) to prove that the cured epoxy resin would not release unreacted monomers to the biological solution test, which caused inhibition of the sensitive biological reactions. By investigating the impact of this process on microchannels’ dimensions and quality, a laser technique using CO2 laser was used in vector mode to engrave into a transparent epoxy resin chip. The resulting microchannels were characterized using 3D laser microscopy. The outcomes of this study showed considerable potential for laser ablation in machining the epoxy-based chips, whereas the microchannels machined by laser processing at an input power of 1.8 W and scanning speed of 5 mm/s have an aspect ratio of about 1.19 and a reasonable surface roughness (Ra) of ~ 15 µm. Meanwhile, the bulge height was 0.027 µm with no clogging, and HAZ was ~ 18 µm. This study validated the feasibility of quick and cost-effective CO2 laser microfabrication to develop epoxy resin-based microfluidic chips without the need for cleanroom facilities that require expensive equipment and lengthy process.

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Section: Heat-affected Zone (Haz)mentioning

confidence: 93%

Section: Microchannel Roughnessmentioning

confidence: 99%

Section: Bulge Heightmentioning

confidence: 99%

Section: Heat-affected Zone (Haz)mentioning

confidence: 99%

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Development of epoxy resin-based microfluidic devices using CO2 laser ablation for DNA amplification point-of-care (POC) applications

Mansour

Soliman

El-Bab

et al. 2022

Int J Adv Manuf Technol

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“…Laser sources used in pulsed ablation of solid materials are classified into two categories; that is, a solid-state medium uses doped crystals or glass, such as Nd:YAG or Ti-Sapphire, and the gas phase (excimer or CO 2 ) uses photoemissions from unstable compounds and decomposition [96]. The selection of the laser source and its wavelength is essential in generating NPs with the desired morphology.…”

Section: Source and Wavelength Of Lasermentioning

confidence: 99%

Influence of Laser Process Parameters, Liquid Medium, and External Field on the Synthesis of Colloidal Metal Nanoparticles Using Pulsed Laser Ablation in Liquid: A Review

2022

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Pulsed laser ablation in liquid, used for nanoparticle synthesis from solid bulk metal targets (a top-down approach), has been a hot topic of research in the past few decades. It is a highly efficient and ‘green’ fabrication method for producing pure, stable, non-toxic (ligand-free), colloidal nanoparticles, which is often challenging using traditional chemical methods. Due to the short time scale interaction between the laser pulses and the target, it is difficult to achieve complete control on the physical characteristics of metallic nanoparticles. Laser process parameters, liquid environment, and external fields vastly effect the shape and structure of nanoparticles for targeted applications. Past reviews on pulsed laser ablation have focused extensively on synthesising different materials using this technique but little attention has been given to explaining the dependency aspect of the process parameters in fine-tuning the nanoparticle characteristics. In this study, we reviewed the state of the art literature available on this technique, which can help the scientific community develop a comprehensive understanding with special insights into the laser ablation mechanism. We further examined the importance of these process parameters in improving the ablation rate and productivity and analysed the morphology, size distribution, and structure of the obtained nanoparticles. Finally, the challenges faced in nanoparticle research and prospects are presented.

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Carbon dots: Types, preparation, and their boosted antibacterial activity by photoactivation. Current status and future perspectives

Lagos

García

Cuadrado

et al. 2023

WIREs Nanomed Nanobiotechnol

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Carbon dots (CDs) correspond to carbon‐based materials (CBM) with sizes usually below 10 nm. These nanomaterials exhibit attractive properties such us low toxicity, good stability, and high conductivity, which have promoted their thorough study over the past two decades. The current review describes four types of CDs: carbon quantum dots (CQDs), graphene quantum dots (GQDs), carbon nanodots (CNDs), and carbonized polymers dots (CPDs), together with the state of the art of the main routes for their preparation, either by “top‐down” or “bottom‐up” approaches. Moreover, among the various usages of CDs within biomedicine, we have focused on their application as a novel class of broad‐spectrum antibacterial agents, concretely, owing their photoactivation capability that triggers an enhanced antibacterial property. Our work presents the recent advances in this field addressing CDs, their composites and hybrids, applied as photosensitizers (PS), and photothermal agents (PA) within antibacterial strategies such as photodynamic therapy (PDT), photothermal therapy (PTT), and synchronic PDT/PTT. Furthermore, we discuss the prospects for the possible future development of large‐scale preparation of CDs, and the potential for these nanomaterials to be employed in applications to combat other pathogens harmful to human health. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease

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Laser ablation

Cited by 14 publications

References 70 publications

Development of epoxy resin-based microfluidic devices using CO2 laser ablation for DNA amplification point-of-care (POC) applications

Development of epoxy resin-based microfluidic devices using CO2 laser ablation for DNA amplification point-of-care (POC) applications

Influence of Laser Process Parameters, Liquid Medium, and External Field on the Synthesis of Colloidal Metal Nanoparticles Using Pulsed Laser Ablation in Liquid: A Review

Carbon dots: Types, preparation, and their boosted antibacterial activity by photoactivation. Current status and future perspectives

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