UV–laser-assisted modification of the optical properties of polymethylmethacrylate

Wochnowski, Carsten; Metev, S.; Sepold, G.

doi:10.1016/s0169-4332(99)00435-3

Cited by 122 publications

(64 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Many studies have indicated that excimer laser ablation can cause scission of various chemical bonds in chains of PMMA including C-C, C-H, C=O, and results in the formation of oxygen-containing species such as carboxylate and hydroxylate groups. Higher fluence leads to formation of much carboxylate groups and further increases the hydrophilicity of PMMA (Wochnowski et al 2000;Johnson et al 2001;McCarley et al 2005). Therefore, from Fig.…”

Section: Hydrophilicity Modification Of Ablated Pmma Microchannelsmentioning

confidence: 94%

Hydrophilicity modification of poly(methyl methacrylate) by excimer laser ablation and irradiation

Huang

Chen

Yao

et al. 2007

Microfluid Nanofluid

View full text Add to dashboard Cite

Because of the micromachining characteristic of excimer laser ablation, the microchannels ablated with this technique on poly(methyl methacrylate) (PMMA) substrate have definite surface roughness. Utilizing this characteristic, the hydrophilicity of PMMA microchannels could be directly modified during fabrication process both by the mechanism of photochemical ablation and the effect of surface roughness. The contact angle is inversely proportional to the surface roughness under ablation with same fluence and could be reduced to 25°by choosing ablation parameters reasonably (7.38 J/cm 2 , 20 Hz, 10 mm/min). Excimer laser irradiation of PMMA substrates for different irradiation times at fluence below the ablation threshold also results in the surfaces becoming more hydrophilic without any marked change in the surface topography. The contact angle decreases with the increase of irradiation times and finally reaches the saturated status after irradiation for 2,500 times. Under same irradiation times, higher fluence led to PMMA substrates more hydrophilic.

show abstract

Section: Hydrophilicity Modification Of Ablated Pmma Microchannelsmentioning

confidence: 94%

Hydrophilicity modification of poly(methyl methacrylate) by excimer laser ablation and irradiation

Huang

Chen

Yao

et al. 2007

Microfluid Nanofluid

View full text Add to dashboard Cite

show abstract

“…the material and formation of free radicals such as • O-CH 3 [11,12]. Consequently the appearance of • O-CH 3 radicals may affect the ionic environment, leading to inhomogeneous broadening of the bands in the Stark structure for the photoluminescence.…”

mentioning

confidence: 99%

Thermal quenching of photoluminescence of Eu3+ ions in an Eu(fod)3 complex

et al. 2006

View full text Add to dashboard Cite

Introduction.Currently transparent polymer materials are being increasingly widely used in optoelectronics. They are used as the basis for designing new types of integrated optics devices such as optical amplifiers, frequency selectors, three-dimensional memory devices, etc. Furthermore, study of the physical and chemical properties of polymers is of significant interest since those properties can change considerably when specific molecular compounds are added.Adding organometallic compounds to the internal free volume of samples using supercritical media, in particular supercritical carbon dioxide (supercritical CO 2 ), in order to modify their optical properties is a very advanced doping method [1,2]. A still unresolved question is how the matrix of the studied materials affects the spectral properties of the organometallics added to them.Such a property of Eu(fod) 3 molecules as the temperature dependence of the photoluminescence intensity in the range 20 o C-100 o C allows us to use doped polymers as highly sensitive temperature sensors which can be utilized, for example, in medicine. Moderate (up to 70 o C-80 o C) local heating of biological tissues by laser radiation is currently being used to correct the shape of the nasal septum, to regenerate intervertebral discs, and to treat tumors by hyperthermia. The required therapeutic effect is usually achieved when changes in the physical and chemical properties (especially mechanical, optical, and thermal properties) occur within the heated tissue interior as determined by the experimental conditions. Controlling the experimental conditions significantly reduces the likelihood of complications after laser procedures, and so monitoring such conditions has become important in both a scientific and practical sense. Designing such a sensor based on the effect of the temperature dependence of photoluminescence provides a noninvasive, rapid, highly sensitive, and optimal method for observing the conditions during laser heating of biological tissues.The aim of this work was to search for optical materials which can be used in designing a temperature sensor, and to study the effect of temperature on the photoluminescent properties of Eu(fod) 3 . In this project, we were guided by the following considerations. First of all, we need to choose a molecular compound that is photostable in the temperature range 20 o C-100 o C and has a sufficiently intense photoluminescence band in the visible region. Secondly, such a compound should be efficiently introduced into the matrices used with the help of supercritical CO 2 . At this time we have studied the process of quenching of the photoluminescence of Eu 3+ ions in several polymer materials such as polymethylmethacrylate (PMMA), polydimethylsiloxane (PDMS), and polypropylene (PP) doped with Eu(fod) 3 . For comparison, we also used the original polycrystalline Eu(fod) 3 powder in the experiments. The doping

show abstract

“…The UV excimer laser has been used to irradiate homogeneous slabs of PMMA in order to modify the refractive index locally in a controllable way at the polymeric substrate surface (Wochnowski et al, 2000;Shams-Eldin et al, 2004, 2005. Thus the integrated optical waveguides can be directly laser-written into the surface of polymeric substrates by employing lithographic masks.…”

Section: Introductionmentioning

confidence: 99%

“…Thus the integrated optical waveguides can be directly laser-written into the surface of polymeric substrates by employing lithographic masks. It is very important that the refractive index is modified in a controllable way by using specific conditions during the irradiation process in order to obtain the desired waveguide structures (Wochnowski et al, 2000). The UV photons of the incident laser radiation do interact with the molecules of the polymeric material due to a UV-photon-induced reaction (Shams-Eldin et al, 2005), so the refractive index at the surface of the PMMA slabs was changed in the irradiated area.…”

Section: Introductionmentioning

confidence: 99%