The correlation between surface tension parameters and the chemical composition of polysulfone, chloromethylated polysulfone and quaternized polysulfone membranes, before and after plasma treatment, was investigated. Calculations are based on the geometric mean approach of Owens, Wendt, Rabel and Kälble, as well as on the theoretical methods involving quantitative structureproperty relationships on the basis of the group contribution techniques. The chemical modifications of polysulfone membranes and the low pressure plasma treatment affect the contact angle corresponding to different liquids. Consequently, the total surface tension and the polar component increase with the substitution degree of chloromethylated polysulfone and with the quaternization degree of the ammonium groups, in quaternized polysulfone samples. The plasma treatment modifies the surface energy of the samples, increasing their surface polarity and wettability. Surface wettability trends were also studied by means of the free energy of hydration between compounds and water.

The correlation between surface tension parameters and the chemical composition of poly(amic acid) and polyimide films, before and after plasma treatment, was investigated. Calculations are based on the geometric mean approach according to Owens, Wendt, Rabel, and Kälble, on the Lifshitz‐van der Waals acid/base approach according to Van Oss, Good, and Chaudhury, as well as on the theoretical method which implies the quantitative structure–property relationships. The polar components for all films investigated contribute significantly to the total surface tensions, as due to the large electron‐donor interactions. Plasma treatment alters the surface energy of samples, changing their surface polarity and wettability. Surface wettability and hydrophilicity trends for poly(amic acid)s and their polyimides were also studied by means of the free energy of hydration between compounds and water. These properties recommend the polyimides as excellent materials for electrical compounds and biomaterials. POLYM. ENG. SCI., 47:381–389, 2007. © 2007 Society of Plastics Engineers.

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Two binary polyimide (PI) blends having a common monomer, diamine and dianhydride, were prepared. The first system was composed of PIs obtained from an alicyclic and flexible dianhydride, namely 5-(2,5-dioxotetrahydrofurfuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride (DOCDA) and two aromatic diamines, 4,4 0 -oxydianiline (ODA) and p-phenylenediamine (PPD), respectively. In the second system, ODA was combined with DOCDA and (hexafluoroisopropyldiene)diphtalic dianhydride (6FDA). Incorporation of aliphatic and asymmetric DOCDA moieties, hexafluoropropyldiene groups and ether linkages in the molecular structure of PI blends, poly(DOCDA/PPD)/poly(DOCDA-ODA) and poly(6FDA-ODA)/poly(DOCDA-ODA) influenced the surface tension parameters, surface and interfacial free energy, and the work of spreading of water, maintaining the surface hydrophobic characteristics of both systems. In addition, it has been found out that surface hydrophobicity and surface roughness are properties that can be correlated with the red blood cells and platelets compatibility. POLYM. ENG.