Nanopore engineered tortuosity towards thermo-mechanically enhanced low-k polymer-mesoporous organosilica composite membranes

Abstract

The continuous development of microelectronics requires mechanically enhanced insulating materials with a lower dielectric (low-k) constant. To accomplish this, in this paper, low-k polymer nanocomposites were reinforced with hydrophobic ethane-bridged mesoporous organosilica (EMO) particles as fillers. In this study, three types of EMOs such as pure EMO, EMO functionalized with trimethoxyphenylsilane (PTS) (EMO-PTS) group, and EMO functionalized with 1-[3-(trimethoxysilyl)propyl]urea (UTS) (EMO-UTS) group were prepared via sol-gel self-assembly method. Mesostructures and surface areas of synthesized EMO particles were successfully characterized by XRD, TEM, and BET, whereas 13C and 29Si CP/MAS NMR spectra were also evidenced the presence of organic functional groups in the final EMO particles. Then, these filler materials were employed along with PMDA-ODA PAA (polyamic acid) solution for making efficient polyimide (PI) polymer composites. The good dispersion of EMO/EMO-PTS/EMO-UTS fillers into polyimide (PI) matrix were investigated using cross-section of scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atom force microscopy (AFM). UV–visible spectroscopy has also shown optical transmittance more than 80% in the visible range. Dielectric constant (DC) was also found to be reduced from 3.42 (in PI) to 2.51 (in polymer composites) upon addition of 2–3 wt% of filler materials. The addition of these fillers into polymer PI has also significantly enhanced modulus, hardness and glass-transition temperature of the final composites. These results strongly suggest that EMO and functionalized EMO with either PTS or UTS could be used as promising “reinforcing mesoporous filler and low-k materials” with polyimide.