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.

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This study presents an investigation on polyimides derived from a unfunctionalized symmetric cyclopentyl-containing alicyclic cardo-type dianhydride with ester linkage 1,1-bis(4-(3,4-dicarboxylbenzoyloxy)phenyl)cyclopentylene dianhydride (BDPCP) that was readily accessed starting from cyclopentanone through two steps in high yield. Two series of polyimides, Cardo-type series (CPIx) and analogous aromatic series (ArPI-x) were prepared from condensation of BDPCP and aromatic 3,3

The structural transformation strategy of cis-5-norbornene-endo-2,3-dicarboxylic anhydride (NA) was performed by esterification. The double bond on the diester of NA showed adequate hydrosilylation reactivity with SiAH bonds of phenylcontaining disiloxane. Thereby, a new siloxane-containing alicyclic dianhydride, 5,5 0 -exo-(1,3-dimethyl-1,3-diphenyl-disiloxane-1,5diyl)bisbicyclo[2,2,1]heptane-2,3-endo-dicarboxylic anhydride 6 was successfully synthesized starting from NA, 1,3-dimethyl-1,3-diphenyldisiloxane and platinum complex catalyst. The whole synthetic route of dianhydride 6 consisted of esterification, hydrosilylation, saponification, acidification, and dehydration. A series of polyimides (PIs) were prepared from dianhydride comonomers of 6 and 4,4 0 -biphenyltetracarboxylic dianhydride (BPDA) in different molar ratio together with the diamine 4,4 0 -oxydianiline (ODA). The thermal and mechanical properties of PIs showed somewhat decrease with increasing content of dianhydride 6. The solubility of PIs increased with the increasing content of dianhydride 6, and further calculation from Bragg's equation indicated that average interchain distance (d-spacing value) increased with increasing content of siloxane and alicyclic segments in the backbone of PIs. It was revealed that the hydrophobicity of PIs increased with the increasing content of dianhydride 6. Polyimide 7g, which was prepared from 100% 6 and ODA, showed water adsorption of less than 0.7% and contact angle against water of 101.1 .