Interactions of Cold Plasmas with Polymers and Their Model Molecules: Degradation vs. Functionalzation

Abstract

The influence of the chemical composition of polymers on their modification in argon or oxygen RF plasmas has been studied. Hexatria-contane (C36), octadecyloctadecanoate (OOD), and octadecyloctadecanamide (OAD) have been chosen as model compounds of the following polymers: high density polyethylene (HDPE), polycaprolactone and two polyamides [nylon 6 (N6) and nylon 12 (N12)]. Surface degradation and functionalization have been followed using gravimetry, optical emission spectroscopy, mass spectroscopy, XPS, and contact angle measurements. The presence of ester or amide functions in the composition of the polymers has an influence on the degradation which starts on the functions. The mechanisms of formation of the degradation products CO and CO₂, followed by mass spectrometry, are the same for all the investigated samples. The competition between degradation and functionalization limits the evolution of the O/C ratio and of the surface energy. A contact angle titration technique showed the formation during plasma treatment of functions which can participate in an acid/base reaction.