Layered polymeric optical systems using continuous coextrusion

Song, Han Wook; Singer, Kenneth D.; Wu, Yan; Zhou, Juefei; Lott, Joe; Andrews, James H.; Hiltner, A.; Baer, E.; Weder, Christoph; Bunch, Robert M.; Lepkowicz, Richard S.; Beadie, G.

doi:10.1117/12.830035

Cited by 15 publications

(20 citation statements)

References 32 publications

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“…[38] Figure 1 shows data from an atomic force microscopy (AFM) scan across a microtomed multilayer slice for a 32layer PS∕PMMA 16 sample of the type assembled for these measurements. Typical layer thickness variations for the process used to create these 32-layer and 128-layer films were the subject of study in [4,39,40]. The thickness distributions were found to have nominal standard deviations of 15% and 24%, respectively, but were not Gaussian [39].…”

Section: Experiments a Materials And Processesmentioning

confidence: 99%

Role of group velocity delay in Faraday rotation in a multilayer polymer lattice

et al. 2012

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We measure and model the spectral dependence of Faraday rotation in one-dimensional lattice structures composed of co-extruded alternating polymer layers of polymethylmethacrylate and polystyrene. We develop a theory that shows that the net Faraday rotation in a symmetric multilayer system is determined not by the total thickness of the constituent materials but by the time spent in each constituent material as measured by the overall group velocity delay of the structure and the relative energy distribution per material. We compare measured and computed Faraday rotation spectra for these films to theoretical predictions, taking into account ellipticity as well as layer thickness variations and finite spectral width detection. To measure rotations of these thin, nonmagnetic, weak Faraday rotators, we constructed and optimized an apparatus capable of measuring broadband Faraday rotation spectra at 0.001°resolution for rotation angles as small as 0.002°.

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Section: Experiments a Materials And Processesmentioning

confidence: 99%

Role of group velocity delay in Faraday rotation in a multilayer polymer lattice

et al. 2012

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“…Among polymer photonic structures, monodimensional multilayered photonic crystals, namely distributed Bragg reflectors (DBRs) and planar microcavities, are the simplest from a fabrication and modelling point of view [33]. Moreover, they are already fabricated industrially via melt processing [34,35]. In addition, these systems are highly versatile.…”

Section: Introductionmentioning

confidence: 99%

Polymeric Planar Microcavities Doped with a Europium Complex

et al. 2020

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Organo-metallic europium complex tetrakis (dibenzoyl methide) triethylammonium (EuD4TEA) shows a sharp emission spectrum, which makes it interesting for photonic applications. In this work, we embedded it into all-polymeric planar microcavities and investigated the effect of the photonic environment on its emission spectrum. To this end, submicron-sized EuD4TEA crystals were loaded into a blend of polystyrene and carboxylic terminated polystyrene matrix, which served to stabilize the emitter in the polymer and to make the composite processable. The new composite was then casted by spin-coating as a defect layer in a polymeric planar microcavity. Spectroscopic studies demonstrate that fine spectral tuning of the cavity mode on the sharp organometal luminescence is possible and produces spectral redistribution of the fluorophore emission, along with a remarkable cavity quality factor.

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“…Additionally, for a photonic crystal material, the spectral width of the reflection bandgap, Δλ, can be defined as :

Δ λ = \frac{4 λ Δ n}{π true(n_{1} + n_{2} true)}

…”

Section: Introductionmentioning

confidence: 99%

“…Multilayer films composed of various polymers, usually have small refractive index contrast. However, by applying a large number of layers this limitation can be reimbursed . A multiplication process based on continuous coextrusion was developed and patented by the Dow Chemical Company and has been used to demonstrate improvements in gas barrier properties, increased impact strength, and colorful iridescence .…”

Section: Introductionmentioning

confidence: 99%

“…Several polymer pairs were characterized in a multilayered structure for enhanced mechanical properties, permeability reduction and tunable optics , including a TPU/PEBAX pair that could be stretched to shift the reflected wavelength . Multilayer systems for a variety of uses have become popular and accessible such as effective light emitters , distributed Bragg reflector resonators and gradient refractive index lenses . In this work, alternate structures of two transparent TPUs were coextruded at low shear rates.…”

Section: Introductionmentioning

confidence: 99%

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Physical coloring of multilayered polymeric structures

Dagan

Naveh

2018

Polymer Engineering & Sci

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Multilayered polymer structures made of two transparent, hyperelastic thermoplastic polyurethanes (TPUs) have been studied. The sheets, made by co‐extrusion and layer multiplication techniques, exhibited “physical coloring”, where a preferred wavelength range was reflected and visualized, due to the refractive index difference and nanometric thicknesses of the alternating layers. The extrusion system comprises two extruders and a series of multiplying units, each doubling the number of layers, such that 12 multiplying units render 212 + 1+1 (= 8,193) layers. For a 0.8 mm‐thick die, the resulting layers after die swell are ∼ 150 nm thick. The extrusion temperatures of both grades were adjusted to equilibrate the viscosities and thus stabilize the layers. TPUs are highly elastic, and large stretching ratios allow for significant reduction in thickness. Physical coloring developed in a controlled, reversible manner. The visual color correlates with elongation, and can be offset by choice of initial thickness. Both reflected and transmitted wavelengths change throughout the whole visible range. A model was developed to fit the reflectance data, by introducing a “stress–volume coefficient” due to volume changes during stretch. This model fits the data very well. Characterization by AFM and TEM showed few discontinuous layers and some defects in the structure, nevertheless the multilayer structure is demonstrated. POLYM. ENG. SCI., 59:112–119, 2019. © 2018 Society of Plastics Engineers

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Layered polymeric optical systems using continuous coextrusion

Cited by 15 publications

References 32 publications

Role of group velocity delay in Faraday rotation in a multilayer polymer lattice

Role of group velocity delay in Faraday rotation in a multilayer polymer lattice

Polymeric Planar Microcavities Doped with a Europium Complex

Physical coloring of multilayered polymeric structures

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