Glow Discharge System
Carbon-stabilized Formvar-coated TEM grids become contaminated with atmospheric hydrocarbons as the grids age, and the working surface µ the carbon-stabilized Formvar µ becomes hydrophobic. Because nanoscale TEM samples are often delivered to the grid surface in aqueous solution, it is advantageous to render that surface hydrophilic again. Glow discharge is a mild argon-plasma etch of the surface of carbon-stabilized Formvar-coated TEM grids that removes atmospheric contaminants and makes the grids hydrophilic for several days. Carbon-stabilized Formvar-coated TEM grids are placed face up on Parafilm in the base of a small plastic Petri dish that fits on the stage within the vacuum chamber of the glow-discharge system. The vacuum chamber is pumped to <20 mTorr, argon is introduced to raise the pressure to between 50 and 100 mTorr, and a relatively weak current is applied to the curved metal electrode in the chamber, above the Petri dish, creating the argon plasma that etches the hydrocarbons away from the surface of the grids. The plasma etch process can take from 30 seconds to 5 minutes.
- Quick etch process (30 seconds to 5 minutes)