Preparation and properties of thin films of hyperbranched polyesters with different end groups

Hyperbranched polyesters (HBP) with different end groups were prepared as t hin films. They were characterized with regard to their chemical compositio n, thickness, optical constants and morphology using infrared spectroscopy, spectroscopic ellipsometry, and atomic force microscopy. The surface prope rties of the films were determined by zeta-potential and contact angles mea surements. The differences in the molecular structure and surface energetic and acid-base properties between HBP materials with carboxylic, hydroxy an d acetoxy end groups result in differences in their swelling behavior in at mospheric humidity. The swelling behavior at different atmospheric humidity was observed in situ using spectroscopic ellipsometry and reflectometric i nterference spectroscopy. From the results it can be concluded that HBP fil ms can be used potentially as sensoric materials.