Investigation of PCM Microcapsules with Paraffin Filling by Positron Lifetime Spectroscopy |
| B. Zgardzińska
Institute of Physics, Maria Curie-Skłodowska University, pl. M. Curie-Skłodowskiej 1, 20-031 Lublin, Poland |
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| Positron annihilation lifetime spectroscopy was applied to investigate the microcapsules composed of n-eicosane (filling material) and polysiloxane polymer (shell) in the range of temperatures 123-333 K. Pure components of microcapsules were also investigated as a base for interpretation of the measurement results. The temperature of phase transitions in microcapsules was determined. It showed the appearance of a rotary phase, which is not present in pure n-eicosane. In the considered material, two types of free volume have been identified. The sizes of free volumes able to accommodate Ps were estimated using standard models. On the basis of the o-Ps intensities, the content of polysiloxane in microcapsules was estimated as about 40%. Internal structure of the microcapsules (morphology) was observed by scanning electron microscopy. |
DOI: 10.12693/APhysPolA.127.1536 PACS numbers: 78.70.Bj; 62.23.Pq; 61.80.Fe; 61.72.-y; 61.46.-w; 81.07.Nb; 64.70.Nd; 82.35.Pq |