Chemical and physical properties of laser-modified polymers

Dunn, Douglas S.; Ouderkirk, A. J.

doi:10.1021/ma00205a013

Cited by 51 publications

(38 citation statements)

References 2 publications

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“…In the mass spectra C 2 H 2 , HCN, CO, CO 2 , C 4 H 2 , and C 6 H 2 could be detected, while the emission spectra showed the C 2 and CN emission lines. The chemical species in the mass spectra were assigned according to the Refs [61] and [162], which used gas-phase FTIR and GC-MS for the assignment of the decomposition products.…”

Section: Resultsmentioning

confidence: 99%

“…These features are found for films and fibers and are attributed to different mechanisms like Marangoni convection [159], surface scattered waves [160], recombination of microcracks [135], and a mixture of several mechanisms [161]. It is also known that the irradiation of stretched polymers results in the creation of microstructures due to the release of the stress fields [52] upon laser irradiation and surface melting, which leads to a crystalline-to-amorphous transition of the polymers [162].…”

Section: Discussionmentioning

confidence: 99%

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Laser Application of Polymers

Lippert

2004

Polymers and Light

150

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Laser ablation of polymers has been studied with designed materials to evaluate the mechanism of ablation and the role of photochemically active groups on the ablation process, and to test possible applications of laser ablation and designed polymers. The incorporation of photochemically active groups lowers the threshold of ablation and allows high-quality structuring without contamination and modification of the remaining surface. The decomposition of the active chromophore takes place during the excitation pulse of the laser and gaseous products are ejected with supersonic velocity. Time-of-flight mass spectrometry reveals that a metastable species is among the products, suggesting that excited electronic states are involved in the ablation process. Experiments with a reference material, i.e., polyimide, for which a photothermal ablation mechanism has been suggested, exhibited pronounced differences. These results strongly suggest that, in case of designed polymers which contain photochemically active groups, a photochemical part in the ablation mechanism cannot be neglected. Various potential applications for laser ablation and the special photopolymers were evaluated and it became clear that the potential of laser ablation and specially designed material is in the field of microstructuring. Laser ablation can be used to fabricate three-dimensional elements, e.g., microoptical elements.Keywords Laser ablation · Ablation mechanism · Photopolymers · Polyimide · Spectroscopy This was not always true, of course. For many years, the laser was viewed as "an answer in search of a question". That is, it was seen as an elegant device, but one with no real useful application outside of fundamental scientific research. In the last two to three decades however, numerous laser applications have moved from the laboratory to the industrial workplace or the commercial market. Lasers are unique energy sources characterized by their spectral purity, spatial and temporal coherence, and high average peak intensity. Each of these characteristics has led to applications that take advantage of these qualities: -Spatial coherence: e.g., remote sensing, range finding and many holographic techniques. -Spectral purity: e.g., atmospheric monitoring based on high-resolution spectroscopies. -and of course the many other applications in communication and storage, e.g., CDs.All of these high-tech applications have come to define everyday life in the late twentieth century. One property of lasers, however, that of high intensity, did not immediately lead to "delicate" applications but rather to those requiring "brute force". That is, the laser was used in applications for removing material or heating. The first realistic applications involved cutting, drilling, and welding, and the laser was little more advanced than a saw, a drill, or a torch. In a humorous vein A.L. Schawlow proposed and demonstrated the first "laser eraser" in 1965 [4], using the different absorptivities of paper and ink to remove the ink without damaging the und...

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Laser Application of Polymers

Lippert

2004

Polymers and Light

150

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“…The agreement for the incidence angle of 45° is less pronounced. The discrepancy may be due to changes of the polymer refractive index induced by the UV laser irradiation as reported earlier [69]. FIB cuts of laser irradiated and gold coated PET samples were investigated by SEM (see Fig.…”

Section: Surface Morphology and Structure Parametersmentioning

confidence: 94%

Gold Nanostructures Prepared on Solid Surface

Siegel¹,

Kvítek²,

Kolská³

et al. 2012

Metallurgy - Advances in Materials and Processes

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“…PLLA crystallinity reduction by laser irradiation with infrared (IR) and green wavelengths has been quantified through wide-angle X-ray diffraction (WAXD) measurements [8]. The same effects have been observed by excimer laser processes operating at ultraviolet (UV) wavelengths with photon energies higher than bond energies [9,10]. It has been shown that surface crystallinity can be reduced with no measurable chemical modifications due to the low radical mobility in the crystal structure [10].…”

Section: Introductionmentioning

confidence: 91%

Effect of Laser-Induced Crystallinity Modification on Biodegradation Profile of Poly(L-Lactic Acid)

Hsu¹,

Tan²,

Yao

2013

Journal of Manufacturing Science and Engineering

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Poly(L-lactic acid) (PLLA) is of interest in drug delivery applications for its biodegradable and biocompatible properties. Polymer-controlled drug delivery relies on the release of embedded drug molecules from the polymer matrix during its degradation. PLLA degradation exhibits an induction period, during which an insignificant amount of degraded products and embedded drug can be released. Due to this induction period, drug release is initially nonlinear, a complication in drug delivery applications. PLLA degradation is a function of crystallinity, such that control over its crystallinity tailors drug release over time. In this study, the effect of laser-induced PLLA crystallinity reduction on degradation is investigated. Samples having lower surface crystallinity are shown to have higher rates of molecular weight reduction and earlier mass loss than nonlasertreated samples, as observed from gel permeation chromatography and mass change. Wide-angle X-ray diffraction measurements show that crystallinity increases with degradation. A numerical model is implemented from hydrolysis and diffusion mechanisms to investigate the effect of laser irradiation on biodegradation. Controlled laser treatment of PLLA offers a method for constant drug release through the reduction of surface crystallinity.

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Chemical and physical properties of laser-modified polymers

Cited by 51 publications

References 2 publications

Laser Application of Polymers

Laser Application of Polymers

Gold Nanostructures Prepared on Solid Surface

Effect of Laser-Induced Crystallinity Modification on Biodegradation Profile of Poly(L-Lactic Acid)

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