Microfluidic Manufacturing Technique: Hot Embossing for Microfluidics
Hot Embossing technique used in microfluidics is a prototype and production method for creating microfluidic structures.
The first step is to create the SU8 mold of the structures you want to stamp in the polymer chip. The resolution you want to get is based on the mould, so the mask to choose is a key element. Resolutions of structures under 10 micron, a chromium mask is needed.
Once the mold is defined and manufacture, the hot embossing process starts. The temperature to reach is very important here. The objective is to get a certain temperature in the process, where the material (a polymer) reaches the glass transition temperature(called Tg and is different for each polymer)
At this temperature the polymer is very “malleable”, so you can set and replicate the SU8 structures of the mould in the polymer.
Once you cool the material above the Tg Temperature it becomes hard and is alike the glass.
With this technique you are able to replicate complicated microfluidic structures in the different materials(polymers) we use, and create different designs/ microfluidic chip from one mold.