OAM-RC

Abstract

Azobenzene-polymers have been the subject of intensive research due to their unique and unexpected properties that allow various applications triggered by light. One of their attractive features is the possibility of changing the orientation of azobenzene through trans-cis-trans photoisomerization cycles to photoinduce birefringerence and linear dichroism in thin polymer films. Polyimide with rigid or polysiloxane with flexible structure, both containing side azobenzene units, have been characterized and compared. The glass transition temperature of the azo-polyimide is 228°C, while that of azo-polysiloxane modified with thymine is 34°C. The polymers present a good thermostability, the degradation process starting over 315°C. The photochromic behavior, determined by the trans-cis isomerization process of azo-groups in solution and in solid state has been investigated. The surface structuring capacity of the polyimide and the modified polysiloxane was performed by using Nd:YAG laser at 355 nm, at two different incident fluence (8.4 and 35mJ/cm2). The results show that the studied polymers have a good surface structuring capacity in different irradiation conditions. For flexible modified polysiloxane it is necessary a low density and a reduce pulse numbers while in the case of rigid polyimide a low pulse numbers and a high energy density it is necessary.

Keywords

Azopolyimide, Azopolysiloxane, Photochromic behaviour, Surface structuring.

Citation

I. SAVA, The effect of chemical structure of the surface structuring capacity of some polymers containing azobenzene side groups, Optoelectronics and Advanced Materials - Rapid Communications, 3, 7, July 2009, pp.718-724 (2009).

Submitted at: April 11, 2009

Accepted at: July 20, 2009