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.