Characterization of a microfluidic device fabricated using a photosensitive sheet

We investigated the characteristics of microfluidic devices fabricated using photosensitive sheets adhered to substrates. We evaluated them in regard to practical criteria, namely chemical resistance, pressure sealing, electrical resistance and elution of ions. No samples exhibited peeling after postbaking when we investigated the adhesion characteristics by dicing. The sheet swelled dramatically on exposure to an alkaline solution. The microfluidic devices consisting of photosensitive sheet sandwiched by two Pyrex substrates and a photosensitive sheet sandwiched by two PMMA substrates had a pressure sealing of 0.6 MPa, were capable of withstanding a pressure of 0.2 MPa for 1 h when ultrapure water was injected. The sheets had a high volume resistivity (9.7 × 10¹² Ω cm) and a high surface resistivity (2.3 × 10¹¹ Ω) after postbaking. Sodium ions were adsorbed onto the photosensitive sheet and then gradually desorbed. The total amount of sodium ion elution per unit area over 24 h was 8.3 × 10^-9 mol mm ^-2 as measured by ion exchange chromatography. These results confirm that microfluidic devices fabricated using photosensitive sheets are suitable for use as disposable devices for certain applications.