Fabrication of Polymer Shells Using a Depolymerizable Mandrel

A new technique for producing hollow shell laser fusion fuel capsules has been developed that starts with a depolymerizable mandrel. In this technique we use poly(α-methylstyrene) (PAMS) beads or shells as mandrels which are overcoated with plasma polymer. The PAMS mandrel is thermally depolymerized to gas phase monomer, which diffuses through the permeable and thermally more stable plasma polymer coating, leaving a hollow shell. Using this technique we made shells from 200 µm to 4 mm diameter with 15 to 100 µm wall thickness having sphericity better than 0.5 µm and surface finish better than 10 nm RMS.