Dynamic heating and cooling AFM measurements can be challenging because the temperature changes can induce considerable drift both in position, and force control. Linked here (http://www.youtube.com/user/BrukerNano) is a video showing a high speed imaging dynamic experiment from 60 C to -2 C. Tip scanning greatly simplifies the temperature control, while low system drift makes possible the stability. PeakForce Tapping (rather than tapping), which “re-zeros” the force every interaction, enables the continuous imaging over the entire temperature range.
The sample is Poly(diethylsiloxane) (PDES). Siloxanes have broad application as greases, lubricants, elastomers and resins. PDES is a liquid crystal at Room Temperature. When heated, PDES transitions into a fully liquid state at it's isotropization temperature of ~ 60 C. Cooling back down, PDES undergoes two mesomorphic transitions:
Liquid -- Liquid Crystal (mesomorphic), Liquid Crystal -- Solid Crystal (~ -2 C).
AFM imaging can be used to study the film nano-morphology, and its changes
at each phase transition.