Atomic Force Microscopy of the MWCNT/PDMS nanocomposite films

AFM micrograph of the unetched MWCNT/PDMS composite without further processing is presented in pictures. It shows a relatively smooth surface with some topographical features consistent with the polymer matrix. The carbon nanotubes embedded in PDMS are not clearly visible on the surface, although slight differences in surface roughness may indicate their presence. The overall, the surface is dominated by PDMS with a uniform texture and minimal visibility of carbon nanotubes.AFM examination of the MWCNT/PDMS nanocomposite etched with HF acid reveals a significantly more textured surface. The etching process removes part of the PDMS matrix, exposing the MWCNTs more clearly on the surface. The AFM scan shows the MWCNTs as elongated structures protruding from the surface, creating a more distinct and rough topography. The contrast between the polymer matrix and the MWCNTs is more pronounced and highlights the fibrous nature of the carbon nanotubes against the smoother PDMS background. Furthermore, it was found that etching MWCNT/PDMS nanocomposite leads to a remarkable decrease of contact resistance, which is crucial for achieving good thermoelectric performance.