Morphological changes in single-walled carbon nanotubes (SWNTs) upon bombardment with 3MeV protons were monitored by transmission electron microscopy in a wide range of irradiation doses. Evident morphological alterations were observed at >0.1 mC, such as curving of the nanotubes, a loss of their straight shape, and formation of short pieces. During further irradiation (doses approaching 1 mC) SWNTs degraded into an amorphous material, although a significant fraction of them were present as pieces of different lengths.

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Knowing the thermal expansion of a material and the correlation analysis of the photoacoustic signals, it is possible to obtain the phase transition temperature and a qualitative curve of the specific heat at constant pressure (Cp) for ceramic materials. This analysis was applied to a BaTiO3 ferroelectric ceramic and a good agreement with previously published Cp versus temperature curves was obtained. Additionally, the phase transition temperature and the Cp curve of a samarium-doped lead titanate ceramic (Pb0.88Sm0.08TiO3) are presented. The phase transition temperature of the Pb0.88Sm0.08TiO3 obtained with this technique was corroborated with classical differential thermal analysis and dielectric permittivity measurements.

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Photoacoustic signals from the ceramic BaTiO3 are analyzed, as a function of temperature close to structural phase transition from tetragonal to cubic at 110 °C. The amplitude of the signals depends on the changes of the thermoelastic properties in the ceramic with temperature. The Curie temperature value for the phase change was reproducible and was found to be 109±6 °C. A comparative analysis of this result with the differential thermal analysis and permittivity techniques is performed. Two changes of sign in the photoacoustic signal are observed, associated with the thermal expansion coefficient behavior in this material near the transition.

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