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The immobilization of gold nanoparticle (AuNP) linear surface assemblies on polycarbonate (PC) melt surface via molding is investigated. The order of the particle assemblies is preserved during the molding process. The assemblies on PC exhibit plasmonic coupling features and dichroic properties. The structure of the assemblies is quantified based on Scanning Electron Microscopy (SEM) and image analysis data using an orientational order parameter. The transfer process from mold to melt shows high structural fidelity. The order parameter of around 0.98 reflects the orientation of the lines and remains unaffected, independent of the injection direction of the melt relative to the particle lines. This is discussed in the frame of fountain flow during injection molding. The particles were permanently fixed and withstood the injection molding process, detachment of the substrate, and extraction in boiling ethanol. The plasmonic particles coupled strongly within the dense nanoparticle lines to produce anisotropic optical properties, as quantified by dichroic ratios of 0.28 and 0.52 using ultraviolet–visible–near-infrared (UV–Vis–NIR) spectroscopy. AuNP line assemblies on a polymer surface may be a basis for plasmonic devices like surface-enhanced Raman scattering (SERS) sensors or a precursor for nanowires. Their embedding via injection molding constitutes an important link between particle-self-assembly approaches for optically functional surfaces and polymer processing techniques. [ABSTRACT FROM AUTHOR]

Thermal induced solid phase polymer reactions between bisphenol-A-based polycarbonate (PC) and polyvinylamine (PVAm) are used to form permanent composite material. The PC-PVAm interface is characterized by infrared (IR) spectroscopy. IR spectra of synthesized reference substances which can be expected after PC-PVAm reaction are recorded and used to identify amidation product structures within the PC-PVAm interphase. Curve fit analysis is performed to isolated sub-bands. The spectral position of the carbonyl absorption band is a suitable marker for the identification of different amidation products. While the formation of urethane and cyclic Allophanate points to the formation of a co-polymer cyclic Urea indicates a PC chain scission without binding between both polymer materials. [ABSTRACT FROM AUTHOR]

The high temperature of the melt during thermoplastic processing is utilized for the surface modification of thermoplastic parts. The approach is demonstrated for polycarbonate as a reactive polymer and polystyrene as a non-reactive polymer. In case of polycarbonate, a polyamine is coupled to the polymer surface by chemical reaction. Functionalized latex beads are used for polystyrene, which are attached to the polymer surface by interdiffusion. Both surfaces adsorb selectively anionic or cationic dyes, respectively. The dyes are used as model compounds to demonstrate the potential of the surface modification approach for the fabrication of microfluidic parts. Those parts may be used for purification, accumulation, and reaction processes. [ABSTRACT FROM AUTHOR]

The surface-reactive injection moulding process is based on the reactive coupling between, e.g., a polyamine and polycarbonate (PC). The reaction takes place in a small layer and within a time of only about 1 μs before solidifying of the melt surface. Kinetic data are difficult to measure under those conditions. By model reactions in solution and in melt, first data on the reaction rate are available. Moulding experiments were made with a polyethylene imine (PEI), labelled with a naphthalimide dye. On injection of a PC melt, PEI layers of different thickness were transferred from the mould to the PC part surface. No significant residues remained on the mould surface. The thickness of the layer on PC was measured before and after solvent extraction. Conditions for best transfer and the maximum layer thickness are discussed. The electrostatic discharging behaviour of those layers on a PC part is shown. [ABSTRACT FROM AUTHOR]

Abstract: A gold nanoparticle layer on a substrate is deposited by electrostatic deposition from a colloidal solution. This layer is transferred to the surface of a polycarbonate sheet by molding. Our investigations reveal that the nanoparticles are almost completely transferred. A random distribution over the surface is found, which is almost equivalent to that on the substrate surface. The particles are embedded into the outermost surface layer of polycarbonate and covered by a polycarbonate layer of about 5nm in thickness. This ensures an effective immobilization of the particles. Such a layer may be used for applications where, for example, a selective surface activation by irradiation is desired. [Copyright &y& Elsevier]