Optical characterization of polycarbonate: Influence of additives on optical properties

Aden, Mirko; Roesner, Andreas; Olowinsky, Alexander

doi:10.1002/polb.21906

Cited by 45 publications

(37 citation statements)

References 10 publications

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“…GPa), and cyclic olefin copolymer (COC, n =1.52, T g = 158 °C, E = 3.0 GPa) for the optical core and cladding, respectively, due to the refractive index contrast and low absorption of both materials in the visible part of the spectrum [35][36][37] . Carbon-black doped conductive polyethylene (CPE, T m = 120°C, resistivity ρ = 3-8×10 2 Ω-m) was used as a recording electrode material.…”

Section: Design and Fabricationmentioning

confidence: 99%

Polymer Fiber Probes Enable Optical Control of Spinal Cord and Muscle Function In Vivo

Froriep

Koppes

et al. 2014

Adv Funct Materials

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Restoration of motor and sensory functions in paralyzed patients requires the development of tools for simultaneous recording and stimulation of neural activity in the spinal cord. In addition to its complex neurophysiology, the spinal cord presents technical challenges stemming from its flexible fibrous structure and repeated elastic deformation during normal motion. To address these engineering constraints, we developed highly flexible fiber probes, consisting entirely of polymers, for combined optical stimulation and recording of neural activity. The fabricated fiber probes exhibit low-loss light transmission even under repeated extreme bending deformations.Using our fiber probes, we demonstrate simultaneous recording and optogenetic stimulation of neural activity in the spinal cord of transgenic mice expressing the light sensitive protein channelrhodopsin 2 (ChR2). Furthermore, optical stimulation of the spinal cord with the polymer fiber probes induces on-demand limb movements that correlate with electromyographical (EMG) activity.

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Section: Design and Fabricationmentioning

confidence: 99%

Polymer Fiber Probes Enable Optical Control of Spinal Cord and Muscle Function In Vivo

Froriep

Koppes

et al. 2014

Adv Funct Materials

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“…This means that the probabilities of forward and backward scattering are equal. A positive value of g indicates forward scattering; for details see [22] and the literature cited there. The results of measurement and calculation for a wavelength of 980 nm (laser wavelength) are presented in Table 1.…”

Section: Simulation Of Beam Distribution and Integrated Intensity In mentioning

confidence: 99%

“…While the surfaces give rise to reflection, volumetric scattering and absorption can occur inside the transparent part due to crystalline structures and/or additives [22]. Due to the scattering process, the intensity distribution in the joining zone, where both parts are in contact, might deviate from the original distribution [23].…”

Section: Simulation Of Beam Distribution and Integrated Intensity In mentioning

confidence: 99%

“…In this way, a laser beam whose integrated intensity distribution in the joining zone is constant will be favorable for laser transmission welding. Besides the optical system, the intensity distribution in the joining zone depends on the optical properties of the transparent part as well [18,21,22].…”

Section: M-shape Properties and Integrated Intensitymentioning

confidence: 99%

“…For the present calculations the value of 1.55 is used for both polymers [24,25]. As discussed in our previous papers [22,23], the values of T, R, Td and the refractive index are used to calculate the scattering coefficient Cs, the absorption coefficient Ca and the anisotropy factor g of the polymers. The magnitude of the anisotropy factor g gives the degree of anisotropy of the scattering process.…”

Section: Simulation Of Beam Distribution and Integrated Intensity In mentioning

confidence: 99%

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Influence of the Laser-Beam Distribution on the Seam Dimensions for Laser-Transmission Welding: A Simulative Approach

Aden

2016

Lasers Manuf. Mater. Process.

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Radiation propagation and temperature development are simulated for lasertransmission welding of polycarbonate and polybutylene terephthalate parts. The simulations are carried out for a Gaussian-and an M-shape laser beam. For polycarbonate the shape of the laser beam is preserved, while for polybutylene terephthalate it is altered due to scattering processes. The resulting intensity and integrated intensity distribution in the joining zone are calculated for both polymers. They give rise to different temperature fields. The dimensions of the model seam are approximated by the dimensions of the melt isotherm. For polycarbonate the seam generated by a Gaussian beam has a non-homogeneous thickness and a width that is smaller than the beam diameter. For an M-shape beam it has a homogeneous thickness and its width scales with the width of the integrated intensity. For polybutylene terephthalate volumetric scattering destroys the original beam shape in the joining zone. The distributions of the integrated intensities and the dimensions of the seam are similar for both types of beams.

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Influence of titanium dioxide pigments on the optical properties of polycarbonate and polypropylene for diode laser wavelengths

Aden

Mamuschkin

Olowinsky

et al. 2013

J of Applied Polymer Sci

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In laser transmission welding of polymers, additives and colorants could influence the welding result. In this work, polypropylene and polycarbonate probes colored with titanium dioxide (TiO2) pigments of various concentrations are investigated. The probes are produced using an extrusion process to obtain a homogeneous distribution of colorants. The TiO2 pigments change the optical properties of the polymers considerably. The measured reflectance increases with increasing pigment load while the transmittance decreases. From the measured data of transmittance, reflectance, and collimated transmittance, the scattering, the absorption coefficient, and the anisotropy factors are calculated. It is shown that the scattering coefficient at 1530 nm (laser) wavelength is smaller than for 968 nm, while the absorption coefficient is negligible for both wavelengths. Scattering coefficient and anisotropy factor are used to simulate the propagation of the laser radiation in the polymers. The influence of the scattering process on the beam propagation is represented by the change of the power density distribution. It is shown that the maximum intensity of the distribution is reduced more than the transmittance with increasing pigment concentration. The effect is higher for 968 than for 1530 nm wavelength making the larger wavelength more favorable for transmission welding

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Optical characterization of polycarbonate: Influence of additives on optical properties

Cited by 45 publications

References 10 publications

Polymer Fiber Probes Enable Optical Control of Spinal Cord and Muscle Function In Vivo

Polymer Fiber Probes Enable Optical Control of Spinal Cord and Muscle Function In Vivo

Influence of the Laser-Beam Distribution on the Seam Dimensions for Laser-Transmission Welding: A Simulative Approach

Influence of titanium dioxide pigments on the optical properties of polycarbonate and polypropylene for diode laser wavelengths

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