One of the strongest man made fibers is Spectra or Dyema. One problem with spectra is that is very weak at elevated temperatures. Here is my concept on using this to make an electrically actuated valve:
The golden thread is a Spectra loop with some nicrome wire wound in it. Hit the nicrome with a electrical current it gets hot and the spectra fails.
Here is a split view of the closed valve:
When the spectra fails the purple plunger is released and the blue piston moves down the fitting. The purple plunger guides the piston to keep is from cocking while it moves down. When it hits bottom the purple piston falls away. Here is a split view of the open valve.
Not sure if this will work, but some time in the next few weeks I will fabricate a test article.