Comparison of methods for the surface free energy determination of polimeric layers aligning liquid crystals

Sebastian FIRLIK, Jarosław MOLENDA ? Institute for Sustainable Technologies – PIB in Radom; Jerzy BORYCKI ? Technical University of Radom, Materials, Technology and Designing Department, Radom

Please cited as: CHEMIK 2010, 64, 4, 238-245

The goal of the study was to compare methods for determination of the Surface Free Energy and its components for poly(amide-ester-imide) layers used to align crystal molecules. Once the polymeric layers were relevantly prepared, their contact angles were measured using standard liquids having known values of the Surface Free Energy. The obtained values of contact angles were used for calculation of the Surface Free Energy and its components using the Fowkes, Owens-Wendt and van Oss-Good methods. Variance and arithmetic averages of standard deviation were calculated consequently. Statistical comparison analysis was performed for the obtained results (F-Snedecore?s test and t-Student?s test). It was found impossible to alternatively use the testing methods while the value of the Surface Free Energy was determined. To get the full description of the interlayer interactions it is necessary to use a number of mathematical models parallelly.

Keywords: Surface free energy, polyimides, liquid crystals, mathematical statistic analysis