Surface Modification of Silicone

Method of Eroding Silicone and Urethane Surfaces Using Metal Hydroxides

The effects of solutions prepared with metal hydroxides and various solvents on silicone and urethane were examined as follows:

• Metal Hydroxides: Potassium hydroxide, sodium hydroxide, barium hydroxide
• Solvents: Methanol, ethanol, isopropyl alcohol, hexane, tetrahydrofuran, water
• Conditions: Samples (silicone and urethane) were immersed in a 5 wt% metal hydroxide solution and subjected to shaking at 37°C for 1 hour. After treatment, the samples were thoroughly washed with deionized water and observed. Evaluation was based on visual appearance.

Results:

1. Both urethane and silicone surfaces turned white under the following conditions:
   • Potassium hydroxide/methanol + hexane
   • Potassium hydroxide/isopropyl alcohol + hexane
   • Sodium hydroxide/isopropyl alcohol
2. The condition thought to have the strongest effect was:
   • Potassium hydroxide/methanol + tetrahydrofuran
3. It is difficult to target urethane alone.

The study found that the most effective method for eroding the surfaces of silicone and urethane is short-term immersion in a mixed solvent solution of potassium hydroxide with methanol and tetrahydrofuran.

Surfaces treated in this manner are negatively charged, so when a cationic surfactant is applied, ionic bonding occurs.

Octadecylammonium chloride aqueous solution

Subsequently, when an anionic substance such as heparin is bonded, a material with long-term antimicrobial properties and sustained-release antithrombotic properties is completed.

With this method, by properly optimizing the conditions, stable performance can be maintained for several months.

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