Y. Travaly et al., THEORETICAL MODELING OF THE NUCLEATION AND GROWTH OF ALUMINUM FILMS THERMALLY EVAPORATED ONTO POLY(ETHYLENE-TEREPHTHALATE) SUBSTRATE, The Journal of adhesion, 66(1-4), 1998, pp. 339-355
The interface between aluminium and poly(ethylene terephthalate) (PET)
has been studied using the density functional theory (DFT) formalism
within the local density approximation (LDA). An examination of the ch
arge transfers during Al bonding with the polymer functional groups pr
ovides a better understanding of the nucleation of the metallic film.
Indeed, when reacting with the doubly-bonded oxygen atom of the ester
function, the metal particle induces strong modifications in the highe
st occupied molecular orbitals (HOMOs) as well as in the lowest unoccu
pied molecular orbitals (LUMOs) of the PET. The shape of the HOMO, HOM
O-3 and HOMO-4 of the Al/PET complex confirms the evolution of the phe
nyl structure to a quinoid structure. We emphasise the extent to which
the reactivity of the PET can be modified after Al interaction with t
he ester function. After losing their aromaticity, the phenyl rings of
the polymer are no longer available for subsequent interactions. Henc
e, we propose that the Al film will then grow following a compact cubi
c stacking on top of Al atoms already fixed on the ester functions.