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This paper presents an efficient pathway to achieve the dielectric constant as low as 2.48 @ 25 °C, 1 MHz for nonporous poly(imide siloxane) films with mechanical and thermal robustness. A symmetric disiloxane-linked alkyl diamine, bis(aminopropyl)tetramethyldisiloxane (BATMS) with a well-defined molecular formula NH2CH2CH2CH2Si(CH3)2OSi(CH3)2CH2CH2CH2NH2, has been used to controllably reduce the dielectric constant of the polymer films by adjusting the loading of BATMS. The thermal stability of all the polymer films remains robust with T5 and T10 no less than 458 and 472 °C, respectively, while the glass-transition temperature decreases with increasing incorporation of flexible disiloxane-alkyl segments into a polymer backbone. There exists a consistent regularity between the thermal, optical, and dielectric properties with the loading amount of BATMS in the polymer films, inferring that the disiloxane-alkyl segments are homogeneously distributed in the polymer backbone. Charge-transfer complex inhibition of polymer films by disiloxane segments has been revealed by an enlarged d-spacing in wide-angle X-ray diffraction spectra and a blue shift in film fluorescence emission spectra. The combined low dielectric constant, robust mechanical and thermal stability, and improved hydrophobicity make the series of BATMS-resulting poly(imide siloxane) films promising candidates for sophisticated flexible microelectronic application.

Microscopic images of a test chart hidden behind a slab of a highly scattering medium were significantly improved by incorporation of a spatial filter located at the back Fourier-transform plane of the objective lens of a microscope. The image quality was shown to be improved further by detection of only the early-arriving photons through time-resolved detection in combination with spatial filtering.

In this study, we present the novel isocyanate microcapsule preparation of poly(urea-formaldehyde) (PUF) embedded with oxygen plasma treated carbon nanotubes (OPCNTs) to improve the micromechanical behavior of microcapsule shells significantly. Isophorone diisocyanate was encapsulated by PUF through in situ polymerization. PUF, PUF with ultrasonically treated CNTs, and PUF with oxygen plasma treated CNTs (OPCNTs) microcapsules were characterized via field emission-scanning electron microscopy, 3D optical microscopy, fluorescence microscopy, laser diffraction analysis, thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy and nanoindentation tests. As a result, OPCNTs modified by hydroxyl, carboxyl, and carbonyl groups, easily forming hydrogen bonds with water, could be highly dispersed in the shells of microcapsules during the thermosetting process. The particle size distributions of the microcapsules range from 10 to 200 mm with different reaction parameters. Although the CNT mass content of the OPCNTs microcapsules, as measured via TGA, is relatively small, the nanoindentation test indicated that the OPCNTs enhance the hardness and the Young's modulus of the microcapsule shells.