Bubble creation and collapse during excimer laser ablation of weak absorbing polymers

Efthimiopoulos, T.; Kiagias, H.; Christoulakis, S.; Merlemis, N.

doi:10.1016/j.apsusc.2008.03.053

Cited by 9 publications

(4 citation statements)

References 25 publications

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“…The gas passed through the molten region and ejected from the bulk to the outside surface of the PET once the bubbles exploded, resulting in formation of craters. This is in good agreement with polymethyl methacrylate craters with the diameter ranging from 5 µm to 20 µm produced by nanosecond UV laser according to the findings of Efthimiopoulos [27] and Britta [28].…”

Section: Resultssupporting

confidence: 89%

Enhancement of Heat Dissipation by Laser Micro Structuring for LED Module

Zhang

2018

Polymers

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Optimization for heat dissipation plays a significant role in energy saving and high-efficiency utilizing of integrated electronics. In this paper, we present a study of micro structuring on polymer-based flexible substrate coupled with aluminum-alloy heat sink. The heat dissipation performance was investigated by temperature evolution of a heat sink under natural convection by infrared (IR) camera, and results showed that the heat dissipation enhancement could be up to 25%. Moreover, the heat dissipation performance of a typical heat sink in terms of light-emitting diode (LED) hip was investigated via both thermal transient measurement and the finite element analysis (FEA). The maximum LED chip temperature of the laser-textured heat sink was approximately 22.4% lower than that of the as-received heat sink. We propose that these properties accompanied with the simplicity of fabrication make laser surface texturing a promising candidate for on-chip thermal management applications in electronics.

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Section: Resultssupporting

confidence: 89%

Enhancement of Heat Dissipation by Laser Micro Structuring for LED Module

Zhang

2018

Polymers

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“…These actions could result in spallation, degradation of the material molecular chains, as well as cavitational effects. The latter process can be due to shocks propagating in a liquid medium (Efthimiopoulos et al 2008), as discussed in Section 3.2.3; laser-induced cavitation has been actually detected in vascular operations (Garnic and Hurwitz 2005).…”

Section: Photoablationmentioning

confidence: 99%

Removing vascular obstructions: a challenge, yet an opportunity for interventional microdevices

Miloro

Sinibaldi

Menciassi

et al. 2012

Biomed Microdevices

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Cardiovascular diseases are the leading cause of death worldwide; they are mainly due to vascular obstructions which, in turn, are mainly caused by thrombi and atherosclerotic plaques. Although a variety of removal strategies has been developed for the considered obstructions, none of them is free from limitations and conclusive. The present paper analyzes the physical mechanisms underlying state-of-art removal strategies and classifies them into chemical, mechanical, laser and hybrid (namely chemo-mechanical and mechano-chemical) approaches, while also reviewing corresponding commercial/research tools/devices and procedures. Furthermore, challenges and opportunities for interventional micro/nanodevices are highlighted. In this spirit, the present review should support engineers, researchers active in the micro/nanotechnology field, as well as medical doctors in the development of innovative biomedical solutions for treating vascular obstructions. Data were collected by using the ISI Web of Knowledge portal, buyer's guides and FDA databases; devices not reported on scientific publications, as well as commercial devices no more for sale were discarded. Nearly 70% of the references were published since 2006, 55% since 2008; these percentages respectively raise to 85% and 65% as regards the section specifically reviewing state-of-art removal tools/devices and procedures.

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“…The reactions last for microseconds after the nanosecond UV laser pulse [21]. After laser treatment, bubbles can be observed on the polymer surface [20,22,23].…”

Section: Interaction Between Photons and Polymersmentioning

confidence: 99%

Effect of excimer laser irradiation of biodegradable polymer on its chemical bonding

Hsu¹,

Tan²,

Yao³

2011

International Congress on Applications of Lasers &Amp; Electro-Optics

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The biodegradable polymer such as poly(L-lactic acid) (PLLA) is promising in drug delivery applications because its chemical structure allows it to hydrolyze into non-toxic substances in the human body. In such applications, drugs are embedded in a polymer matrix and released at the rate at which it degrades. PLLA degradation rate of is a strong function of its crystallinity. Thus, control over crystallinity allows for continuous modification of drug release profiles. The excimer laser is used in this study to induce surface crystallinity changes because its spatially uniform intensity profile is favorable for surface treatment. The effects of excimer laser irradiation on the surface morphology, crystallinity, and chemical modifications are investigated via optical microscopy, wide-angle X-ray diffraction, and X-ray photoelectron spectroscopy. A model is developed to numerically examine the spatial and temporal temperature profiles, as well as the amount of chemical modifications. It is found that PLLA crystallinity decreases as a function of laser fluence, and that the amount of chemical modifications is minimized by annealing before laser treatment and reducing laser fluences, which decrease free radical mobility and thus the dissociation quantum yield. A working window is demonstrated in which PLLA crystallinity decreases with no measurable chemical modifications, and the working window can be enlarged by decreasing free radical mobility.

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Bubble creation and collapse during excimer laser ablation of weak absorbing polymers

Cited by 9 publications

References 25 publications

Enhancement of Heat Dissipation by Laser Micro Structuring for LED Module

Enhancement of Heat Dissipation by Laser Micro Structuring for LED Module

Removing vascular obstructions: a challenge, yet an opportunity for interventional microdevices

Effect of excimer laser irradiation of biodegradable polymer on its chemical bonding

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