• DOI:10.1007/S10404-012-0966-Y
• Corpus ID: 93233494

Microfluidic motion for a direct investigation of solvent interactions with PDMS microchannels

@article{Bianco2012MicrofluidicMF,
  title={Microfluidic motion for a direct investigation of solvent interactions with PDMS microchannels},
  author={Monica Bianco and Ilenia Viola and Miriam Cezza and Francesca Pietracaprina and Giuseppe Gigli and Rosaria Rinaldi and Valentina Arima},
  journal={Microfluidics and Nanofluidics},
  year={2012},
  volume={13},
  pages={399-409}
}

• M. Bianco, I. Viola, +4 authors V. Arima
• Published 21 March 2012
• Engineering
• Microfluidics and Nanofluidics

Solid surface/liquid interactions play an important role in microfluidics and particularly in manipulation of films, drops and bubbles, a basic requirement for a number of lab-on-chip applications. The behavior of solvents in coated microchannels is difficult to be predicted considering theories; therefore, experimental methods able to estimate the properties at the interface in real time and during the operational regime are amenable. Here, we propose to use an experimental setup to evaluate the effective dynamics of solvents inside PDMS microchannels. The influence of the solvent properties as well as of the channel wall’s wettability on the fluid movements was evaluated. Modification of the channel properties was achieved by introducing Teflon coatings that allow producing stable hydrophobic microchannel walls. The results were fitted according to Washburn-type power-law and compared with theoretical calculations of the parameter β that expresses the dependence of capillary dynamics on surface tension γ, liquid viscosity η, contact angles θ and the hydraulic radius RH. A comparison between the calculated and the experimental values reveled that parameters other than the contemplated ones influenced the measurements. The main parameter that affects the flow of solvents such as water, methanol ethanol, dimethylformamide, acetonitrile and acetone was found to be the γ/η ratio. Considering these results, the investigation tool described here is believed to be promising to predict the dynamics of common organic solvents inside integrated functional fluidic devices and to accurately control solvent flow, particularly in capillary-driven pumpless systems, a basic requirement for widening the application range of PDMS lab-on-chip devices.