Semi-crystalline polypyrrole:polystyrene sulfonate (PPy:PSS) composites were synthesized successfully after passing through the micro-pores of filter paper. Filter paper was used as a tunnel to channel the diffusion speed of the initiator and to separate the PSS chains as a function of the occupied pore volume. Fourier transform infrared spectroscopy (FT-IR) suggested the specific bonding structures of the formed PPy:PSS. The crystallographic structures of the PPy:PSS composites were analyzed by X-ray diffraction based on various pore sizes of the filter paper used. The crystallinity dependence of the conductivity was evaluated using a standard four-point probe. A series of PPy:PSS samples with different crystallinity exhibited electrical conductivity ranging from 0.007 S/cm to 0.062 S/cm. POLYM. ENG. SCI., 58:1033-1036, 2018. (c) 2017 Society of Plastics Engineers