Optical Properties of Thin Films of DNA-CTMA and DNA-CTMA Doped with Nile Blue

Abstract

Refractive index dispersion of thin films of deoxyribonucleic acid (DNA)-surfactant (CTMA) and doped DNA-CTMA-Nile Blue (NB) (5 w%) complexes are reported and discussed. The thermal variation of the thin film thickness was measured by ellipsometry. The DNA-CTMA complex exhibits a rarely observed negative thermal expansion between room temperature and ca. 85°C. Doping with NB decreases the temperature range of negative thermal expansion to between room temperature and ca. 70°C. The dopping by 5 w% of NB lowers the absolute value of negative thermal expansion of DNA-CTMA system from 5% to 2% within this temperature range.

Keywords:

• Deoxyribonucleic acid
• DNA-CTMA complex
• negative thermal expansion
• Nile Blue
• refractive index dispersion
• thermal dilatation
• thin films

Acknowledgments

E. Hebda, J. Jancia, J. Niziol and J. Pielichowski acknowledge the financial support of Polish National Science Centre through the grant no.0891/B/H03/2011/40 and by the Polish Ministry of Science and Higher Education. F. Kajzar, I. Rau and A. Tane thank the support of European Social Fund through the Sectorial Operation Programme Increasing Economical Competitivity, under POS CCE nr. 634, SMIS 12575 Program. A. Tane acknowledges the financial support of the Sectorial Operation Programme Human Resources Development 2007-2013 of the Romanian Ministry of Labour, Family and Social Protection through the Financial Agreement POSDRU/107/1.5/S/76909.