Team:TU Darmstadt/Protocols/Surface analysis of polyethylene terephthalate with atomic force microscopy

Surface analysis of polyethylene terephthalate with atomic force microscopy (AFM)

Theory

Atomic force microscopy is used to make very precise surface analysis up to nanometer scale. The goal was to indentify differences between different modifications of polyethylene terephthalate and to proof enzymatic degradation by changed surface properties.

Testing

Experiment 1

Pieces of a PET water bottle are melted between two metal plates using a heat gun to create flat samples. They are incubated for 24 h at 37 °C after applying a solution of 90 µmol/L FsC and 90 µmol/L pNB-Est13 without beeing moved. The Samples are washed with distilled water and dried in a cabinet dryer at 60 °C for 1 h. The samples are investigated using AFM.

Experiment 2

Pieces of PET foil are added to solutions of 2 µmol/L FsC and pNB-Est13. In case of pNB-Est13 various concentrations are tested (50 µmol/L; 20 µmol/L; 2 µmol/L). The solutions are constantly agitated in 50 mL falcon tubes. After 7 days the samples are washed with distilled water and dried in a cabinet dryer at 60 °C over night. The samples are investigated using AFM.