A
film in which mass transfer can occur between the
film and the coexisting bulk phases, for all the components. The term
partly open film applies to a
film in which mass transfer can occur only for certain components. The term
closed film applies to those films with fixed mass.
Source:
PAC, 1994, 66, 1667
(Thin films including layers: terminology in relation to their preparation and characterization (IUPAC Recommendations 1994))
on page 1671