Prilagoditev lastnosti površine polietilen tereftalata (PET) z obdelavo v kisikovi plazmi

Modification of surface properties of poly(ethyleneterephtalate) (PET) thin films by treatment with weakly ionized oxygen plasma was studied by contact angles of water and diiodomethane (DIM) drops. Samples were exposed to oxygen plasma with the ion density of 5 x 1015/m[sup]3 and the neutral oxygen atom density of 3 x 1021/m[sup]3. Just after the treatment they were characterized by contact angle measurements. Results showed a quick decrease of the water contact angle in the first few seconds of plasma treatment, while prolonged treatment did not cause any substantiated modification. The contact angles of DIM, on the other hand, remained rather constant for the first several secondsof plasma treatment, and increased after prolonged treatment. It was found that the dispersion component of the surface free energy decreased with increasing treatment time, while the polar component increased with treatment time. The results were explained by surface functionalization as well as by roughness effects.Površinske lastnosti polimera polietilentereftalata (PET) smo prilagodili specifičnim zahtevam po visoki hidrofilnosti z obdelavo v kisikovi plazmi. Stopnjo hidrofilnosti smo določali iz meritev stičnih kotov dveh kapljevin, in sicer vode in dijodometana. Vzorce smo obdelovali v kisikovi plazmi z gostoto ionov 5 x 1015/m[na]3 in gostoto nevtralnih kisikovih atomov 3 x 1021/m[na]3. Meritve stičnih kotov kapljic smo opravili takoj po plazemski obdelavi. Rezultati so pokazali hiter padec stičnega kota vodnih kapljic že v prvih sekundah plazemske obdelave. Podaljšan čas obdelave ni prinesel bistvenih sprememb. Stični koti dijodometana so ostali praktično nespremenjeni po prvih nekaj sekundah, z nadaljnjo obdelavo pa so začeli padati. Ugotovili smo, da disperzijska komponenta površinske energije počasi pada s plazemsko obdelavo, medtem ko polarna komponenta raste. Rezultate smo pojasnili s površinsko funkcionalizacijo polimera in povečano hrapavostjo površine