Multimode 8 atomic

AFM data was acquired using a Multimode 8 atomic force microscope with a NanoscopeV controller (Bruker) and a “E” scanner. Nanoscope software version 9.1 was used to control the microscope. The system was operated in ScanAsyst in Air mode as a peak force tapping mode at ultra-low forces minimize damage to the samples. For reducing vibrational noise, an isolation table/acoustic enclosure was used (Veeco Inc., Metrology Group). Silicon tips on silicon nitride cantilevers (ScanAsyst, Bruker) were used for imaging. The nominal tip radius was approximately 2 nm, resonant frequency 150 kHz, and spring constant k ~0.7 nm⁻¹. The AFM data were analyzed with NanoScope Analysis 1.5 software (Bruker). The sample was prepared by adding 2 µl of 1 onto a clean silicon wafer and drying in air.

The surface morphology and the root mean square roughness of solvent-cast PHB films surfaces were determined using a MultiMode 8 atomic force microscope (Bruker, Santa Barbara, CA, USA). The characterization of each sample was performed in Peak Force (PF) Quantitative Nanomechanical Mapping (QNM) mode, in air, using silicon nitride tips at a scan rate of 1 Hz and a scan angle of 90°. The image processing and data analysis were conducted with NanoScope software version 1.20.