Well encapsulated hollow borosilicate glass sphere@polypyrrole composite with low density, designable thickness and conductivity

Metal or alloy hollow structures were studied to synthesis low density conducting materials, while conducting polymer received more attention for its low-cost and environmental stability. A buffer system was constituted in this paper, which can reduce concentration gradient in polymerization process to improve uniformity and conductivity. A simple route has been developed to obtain low density core–shell hollow borosilicate glass sphere (HBGS)@polypyrrole composite. Polypyrrole (PPy) was chemically grafted from amino group rich layer onto HBGS. H2O/C2H5OH/5-sulfosalicylic acid/pyrrole/FeCl3 system could be regarded as a polymerization buffer system. Fourier infrared spectrum (FT-IR) and X-ray diffraction (XRD) analysis confirmed the perfect capsulation. Scanning electron microscope (SEM) images showed the thickness and surface morphology. Thermogravimetric analysis was conducted to investigate the thermal stability. The conductivity was determined using standard four-point probe method. The probable formation mechanism of the system was proposed on the basis of the experimental results, correlative formula was also calculated fitting the modules.

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► Hollow borosilicate glass spheres@polypyrrole composites with core–shell structure.
► 5-Sulfosalicylic acid (SSA): emulsifier, dopant and chelate reagent with initiator.
► H2O/alcohol/SSA/pyrrole/FeCl3 appears to be buffer system for polymerization.
► Thickness and conductivity was designable and correlative formula fits the modules.