Polymeric One‐Dimensional Photonic Crystals by Continuous Coextrusion

Abstract

It is shown that narrowband one‐dimensional photonic crystals can be fabricated from polymeric materials using laboratory scale layer‐multiplying coextrusion technology. The tuning of the photonic bandgap is demonstrated with films that selectively filter different regions of the visible electromagnetic spectrum. The layer uniformity of the photonic crystals is evaluated by comparing the measured UV‐vis transmission spectra with model simulations, and is independently confirmed with atomic force microscopy. Assemblies of alternating polystyrene and poly(methyl methacrylate) layers exhibit a narrow reflection band with close to 100% reflection in good agreement with the prediction for uniform layers. The flexibility of the process is demonstrated by the fabrication of elastomeric one‐dimensional photonic crystals. It is anticipated that this technology will enable the rapid and facile realization of new polymeric optical devices.magnified image

The effect of strain-hardening on the morphology and mechanical and dielectric properties of multi-layered PP foam/PP film

“…Therefore, it is important to optimize the rheological properties of the PP resins in order to deliver good foam products, with well-controlled cell type, size and density. Finally, the continuous microlayer co-extrusion technique has yielded improved mechanical, optical, transport, and dielectric properties of polymeric materials in layered structures by increasing the number of layers [29][30][31][32]. This technique can also lead to better morphology of PP/PP foam via the layer confinement that the PP film layers provide and suppress the growth of the PP foam layers, resulting in smaller cell sizes and narrow cell size distribution.…”

“…Three complementary approaches are possible in order to obtain a microcellular PP foam/film with improved foaming behavior and morphology that can mimic that of cork: the use of a nucleating agent, the incorporation of long chain branches, and processing via continuous microlayer co-extrusion [19][20][21][22][23][24][25][26][27][28][29][30][31][32]. A nucleating agent is helpful to nucleate and crystallize polypropylene earlier in the cooling process at a faster rate [20][21][22][23].…”

Visualization of Polymer Deformation Using Microcapsules Filled with Charge-Transfer Complex Precursors

“…As an alternative to such molecular mechanisms, several mechanochromic materials based on dynamic photonic crystals have been investigated. [15][16][17] In this case, the deformation changes the geometry of the spatially periodic variation of the multicomponent material, which in turn alters the photonic band gap, i.e., the frequency regime in which incident light is reflected.…”

Artificial latex-based opals prepared by spin casting of monodispersed nano particles

“…Polymers are among the materials, which are used to fabricate of photonic crystals. The polymer photonic crystals (PPC) have been produced via different techniques such as melt compression [2][3][4][5][6], synthetic procedures [7][8][9][10][11][12][13], nanoimprint lithography [14], continuous coextrusion [15,16], layer-by-layer process [17][18][19][20], etc. These structures are first synthesized in a dispersion form, then, the crystalline structure of polymer particles would be obtained after drying the dispersion.…”