title: Nanoscale characterisation and imaging of partially amorphous materials using local thermomechanical analysis and heated tip AFM.
abstract: OBJECTIVE
  The purpose is to investigate the use of thermal nanoprobes in thermomechanical and heated tip pulsed force modes as novel means of discriminating between amorphous and crystalline material on a sub-micron scale.
  
  
  METHODS
  Indometacin powder was compressed and partially converted into amorphous material. Thermal nanoprobes were used to perform localised thermomechanical analysis (L-TMA) and heated tip pulsed force mode imaging as a function of temperature.
  
  
  RESULTS
  L-TMA with submicron lateral spatial resolution and sub-100 nm depth penetration was achieved, allowing us to thermomechanically discriminate between amorphous and crystalline material at a nanoscale for the first time. The amorphous and crystalline regions were imaged as a function of temperature using heated tip pulsed force AFM and a resolution of circa 50 nm was achieved. We are also able to observe tip-induced recrystallisation of the amorphous material.
  
  
  CONCLUSIONS
  The study demonstrates that we are able to discriminate and characterise amorphous and crystalline regions at a submicron scale of scrutiny. We have demonstrated the utility of two methods, L-TMA and heated tip pulsed force mode AFM, that allow us to respectively characterise and image adjacent amorphous and crystalline regions at a nanoscale.
  
  
  CONCLUSIONS
  The study has demonstrated that thermal nanoprobes represent a novel method of characterising and imaging partially amorphous materials.
authors.affiliation: School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK.
authors.forename: Ljiljana
authors.initials: L
authors.lastname: Harding
authors.forename: William P
authors.initials: WP
authors.lastname: King
authors.forename: Xuan
authors.initials: X
authors.lastname: Dai
authors.forename: Duncan Q M
authors.initials: DQ
authors.lastname: Craig
authors.forename: Mike
authors.initials: M
authors.lastname: Reading
mesh_terms: D003460:Crystallization; D006358:Hot Temperature; D007213:Indomethacin / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D036103:Nanotechnology
chemical_list: D007213:Indomethacin