The University of Aveiro
thermal research laboratory


Sub-surface characterization of polymeric composites via Scanning Thermal Microscopy

Standard Atomic Force Microscopy (AFM) topography analysis is well known to present highly detailed information on the surface of materials at the nanoscale. We contrast this information to Scanning Thermal Microscopy (SThM) measurements, performed using the Park XE7 AFM with SThM module, on a composite of polylactic acid (PLA, main phase) with 0.5% graphene oxide, synthesized by Prof. Ana Barros and Dr. João Campos (CICECO and Chemistry Department - University of Aveiro).

Fig. 1a shows an AFM topography image of a 15x15 μm area of the PLA membrane with 0.5% graphene oxide.

Figs. 1b and 1c show, respectively, simultaneously collected topography and thermal conductivity contrast scans performed by the thermal nano-probe for an area of 8x8 μm of the same sample.

A comparison between Figs. 1a, 1b and 1c indicates that thermal conductivity contrast scans provide detailed information on the entwining of polymeric chains which eludes surface topographical analysis performed with both thermal and conventional AFM probes. This illustrates the technique’s ability to perform sub-surface imaging through thermal conductivity contrast analysis, which in the present example opens the possibility to assess, for instance, the density of polymer and chains interactions/free volume.
Fig. 1a
Fig. 1b
Fig. 1c