Kit for Creating Hydrophilic PDMS Surfaces

Material Matters 2008, 3.2, 47.

This kit (Product No. 701912) enables the creation of a durable hydrophilic PDMS surface appropriate for multiple printing applications using hydrophilic inks. After treatment, water should completely wet the surface as the water contact angle is expected to be between 25 and 35°.

Kit Components

Solution A (glycidyl methacrylate-based polymer) Solution B (acrylamide/acrylic acid-based polymer) Ethanol (Product No. 245119) Methylethylketone  Water (Product No. 320072)

10 mL 4 mL 1 L 1 L 500 mL

Standard Surface Modification Procedure:

1. Pre-Treatment

PDMS surface should be activated using a low frequency air plasma treatment for 1 min. (Recommended plasma cleaners Product No. Z561673, Z561681, Z561657, or Z561665).

2. Pre-Rinsing

Rinse the plasma-activated PDMS sample by washing with ethanol for at least 10 min. Repeat the rinsing procedure 3 times. Air dry the sample for at least 15 min. The water contact angle of such obtained activated PDMS surface is expected to be within a 25–40 ° range.

3. First Modification Step

The surface of the horizontally positioned sample prepared in the previous step should be covered with Solution A, typically ~1 mL of the solution per square inch of the surface. The sample should be dried under ambient conditions for 20–30 minutes and annealed at 110 °C under nitrogen or argon for 30 minutes.

4. Rinsing

Rinse the annealed sample three times with methylethylketone for 10 min each time. Then, it should be air-dried for at least 30 min.

5. Polymer Grafting

Add 6 mL of ethanol to the container containing Solution B. The mixture should be homogenized by careful stirring. The surface of the horizontally positioned sample prepared in the previous steps should be treated by completely covering the area to be modified with the homogeneous solution, which typically takes ~1 mL per square inch of the surface. The sample should be dried at ambient conditions for 20–30 minutes, then annealed at 80 °C for 14 hrs. Finally, the unattached polymer should be removed from the sample by a thorough rinse with water and the sample air-dried at room temperature.