Low-cost fabrication of a polydimethylsiloxane (PDMS) microreactor using an improved Print-and-Peel (PAP) method and its performance testing in silver nanoparticle synthesis

Abstract

Abstract A polydimethylsiloxane (PDMS) microreactor was fabricated using an improved Print-and-Peel (PAP) method. Its performance in terms of conversion was studied by observing the formation of silver (Ag) nanoparticles within the microreactor. Using an improvised LEGO® microsyringe pump, 0.001 M silver nitrate (AgNO3) and 0.002 M sodium borohydride (NaBH4) were introduced in the microchannels. Microreactor length and pumping speed were varied, and their effects on conversion were determined. Results showed that conversion increases with reactor length. Conversions in low speed (130 rad/s) were found to be higher than those in high speed (269 rad/s). Highest conversion of 32.52% was obtained for the 16-mm microreactor at low speed. The mean nanoparticle size of 24 nm measured through Scanning Electron Microscopy (SEM) is smaller than the range of 30 to 60 nm in the macroscale set-up. Spectrophotometric analysis showed that the particle size distribution in the microscale is narrower compared to that of the macroscale indicating the formation of more homogeneous and monodispersed nanoparticles in the microreactor. From the cost analysis, the cost of fabrication is fifty-fold less than that of commercial fabrication. Hence, the fabricated microreactor provides a competitive alternative for conventionally-produced microreactors