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 after applying a solution of FsC and Est13. 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. FsC induced surface modification of PET could be observed. There was no surface modification for Est13.

Experiment 2

Pieces of PET foil are added to solutions of FsC and Est13. In case of Est13 various concentrations are tested (50 mmol/L; 20 mmol/L; 2 mmol/L). 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. FsC induced surface modification of PET could be observed. There was no surface modification for no concentration of Est13.