Determining the optimal PDMS–PDMS bonding technique for microfluidic devices

A number of polydimethysiloxane (PDMS) bonding techniques have been reported in the literature over the last several years as the focus on multilayer PDMS microfluidic devices has increased. Oxygen plasma bonding, despite cost, additional fabrication time and inconsistent bonding results, has remained a widely used method for bonding PDMS layers. A comparative study of four rapid, inexpensive alternative PDMS–PDMS bonding approaches was undertaken to determine relative bond strength. These include corona discharge, partial curing, cross-linker variation and uncured PDMS adhesive. Partial curing and uncured PDMS adhesive demonstrated a considerable improvement in bond strength and consistency by retaining average bond strengths of over 600 kPa, which was more than double the average bond strength of oxygen plasma. A description of each technique and their performance relative to oxygen plasma bonding is included.