Incorporation of lead phthalocyanine into periodic nanolayered assemblies for advanced optical systems

Abstract

Periodically structured polymeric materials can lead to the next generation of electro-optic and nonlinear optical devices for applications in information technology. Layer-multiplying melt coextrusion is an attractive method for fabricating periodic structures with thousands of alternating polymer microlayers or nanolayers. Many advanced applications for periodic polymeric structures would be enabled by locating a photoactive dye in one or both layers. However, it is anticipated that due to the thinness of the individual layers and the relatively low molecular weight of many dyes, a substantial fraction of the dye will diffuse from the doped layers into the undoped layers during melt coextrusion. In the present study, we demonstrate two methods for confining the activity of a photoactive dye, lead phthalocyanine, to the doped layers. Polycarbonate containing lead phthalocyanine was coextruded with undoped polyester as an assembly of 128 alternating 86 nm-thick layers. Using the absorption spectra, we demonstrated that a high concentration of the monomer form persisted in the polycarbonate layers, whereas the lead form was converted to the less active lead-free form in the polyester layers. Thus, the active monomer form of PbPc(b-CP) 4 was maintained selectively in the polycarbonate layers. In the second approach, the coextrusion process was altered so that the alternating polycarbonate and polyester layers were separated by a thin layer of a barrier polymer. The barrier layer prevented diffusion of the dye during melt coextrusion and the dye remained selectively in the polycarbonate layers.

Electromechanical deformation and failure of multilayered films

“…The rheology of the polymer was characterized via a melt flow indexer (MFI), Kayeness Galaxy 1, at a shear rate similar to extrusion conditions (10 s −1 ). PC/PVDF multilayered films having a 50/50 layer composition comprising 2,4,8,16,32,64,128,256, and 512 layers were produced. The overall film thickness of 18 ± 1 μm was held constant for all films throughout this investigation.…”

“…For synthetic polymeric systems, layered processing is one of the most practical approaches to facilitate these complex structures 1–3 . In recent decades, a novel forced assembly multilayer coextrusion technology has been attracting both academic and industrial interest for the fabrication of uniquely structured polymeric systems that address a wide range of applications 4–8 . The benefits of this novel multilayering process includes flexibility, versatility, and precise control of the structural levels in addition to being solvent free and a continuous processing of materials 1,9 .…”

“…[1][2][3] In recent decades, a novel forced assembly multilayer coextrusion technology has been attracting both academic and industrial interest for the fabrication of uniquely structured polymeric systems that address a wide range of applications. [4][5][6][7][8] The benefits of this novel multilayering process includes flexibility, versatility, and precise control of the structural levels in addition to being solvent free and a continuous processing of materials. 1,9 The forced assembly multilayer coextrusion process enables many polymeric systems having unique architectures to be produced including multilayer films, 10 cellular film/foam materials, [11][12][13][14] and fibrous membrane systems.…”

Fracture phenomena in micro‐ and nano‐layered polycarbonate/poly(vinylidene fluoride‐co‐hexafluoropropylene) films under electric field for high energy density capacitors

“…This technique enables fabrication of polymer films that contain up to thousands of alternating two or three polymeric layers with a continuous layer thickness down to 10 nm. The production of nanometer‐scale polymer layers has been proven to be able to enhance dielectric, optical, mechanical, and gas transport properties.…”