An evacuated container assembly suitable for use in connection with blood collection including: (a) a container member formed of a first polymeric material and having a sidewall and one or more openings； (b) a nanocomposite barrier coating disposed on the container member having a thickness of up to about 30 microns and being derived from an aqueous dispersion including (i) a dispersed barrier matrix polymer； and (ii) a substantially exfoliated silicate filler having an aspect ratio of more than 50； and (c) one or more sealing members disposed in the opening(s) operative to hermetically seal the cavity； wherein the cavity is evacuated and maintains a pressure below atmospheric pressure and exhibits a draw volume loss lower than that of a like assembly without a nanocomposite barrier film by a factor of at least 1.5.
