Internal modification of poly(dimethylsiloxane) microchannels with a borosilicate glass coating
J-B Orhan1, V K Parashar, J Flueckiger
1Laboratory of Microsystems, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
Langmuir : the ACS Journal of Surfaces and Colloids
|July 26, 2008
Summary
We developed a new method to coat poly(dimethylsiloxane) (PDMS) microchannels with a protective borosilicate glass layer. This inert coating enhances microchannel durability and prevents chemical damage, improving their performance in various applications.
Area of Science:
- Materials Science
- Chemical Engineering
- Microfluidics
Background:
- Poly(dimethylsiloxane) (PDMS) is widely used in microfluidics due to its biocompatibility and ease of fabrication.
- However, PDMS is susceptible to swelling and chemical degradation when exposed to organic solvents and harsh chemicals.
- This limits its application in certain microfluidic devices requiring chemical resistance.
Purpose of the Study:
- To develop an in situ coating technique for PDMS microchannels using borosilicate glass.
- To create a protective and chemically inert layer that enhances the durability of PDMS microchannels.
- To demonstrate the effectiveness of the coating against chemical attack and diffusion.
Main Methods:
- An original in situ coating technique using an active nonaqueous and alkali-free precursor solution.
- Chemical reaction within the microchannel followed by thermal annealing to form the glass coating.
- Characterization using Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy, Nuclear Magnetic Resonance (NMR) spectroscopy, Thermal Gravimetric Analysis (TGA), X-ray Photoelectron Spectroscopy (XPS), Atomic Force Microscopy (AFM), and Scanning Electron Microscopy (SEM).
Main Results:
- A smooth, crack-free, and covalently bonded borosilicate glass coating on PDMS microchannels was successfully achieved.
- The coating demonstrated excellent chemical inertness and acted as an efficient barrier against the diffusion of rhodamine B dye.
- The borosilicate coating prevented PDMS swelling and structural damage when exposed to toluene.
Conclusions:
- The developed in situ borosilicate glass coating technique provides an effective solution for enhancing the chemical resistance and durability of PDMS microchannels.
- This method offers a promising approach for expanding the application range of PDMS-based microfluidic devices, particularly in environments involving harsh chemicals.
- The inert glass coating ensures the structural integrity and performance of microfluidic devices under demanding conditions.
