[7p-A409-1~5] 4.7 Terahertz Photonics

▲ [7p-A409-5] Large optical anisotropy in deformed rubber composites with conductive fillers
revealed by terahertz polarization spectroscopy

〇Makoto Okano¹, Misako Fujii¹, Shinichi Watanabe¹ (1.Keio Univ.)

Keywords:Terahertz spectroscopy, Elastomer, Anisotropic dielectric responses

Terahertz time-domain spectroscopy (THz-TDS) is a emerging and powerful tool for investigating polymeric materials, because terahertz wave can penetrate visibly opaque polymers and the intermolecular vibration mode of polymers exist in the terahertz frequency range. Recently, a polarization sensitive (PS) THz-TDS technique has been developed and improved. The PS THz-TDS enable us to reveal the anisotropic optical responses due to the orientation of the molecular chains and the conductive additives. In particular, we discovered that rubber materials with conductive carbon black (CB) fillers shows strong anisotropy in the dielectric responses due to the orientation distribution of the CB aggregates, and their anisotropy is strongly modulated by the mechanical stretching. In this paper, we revealed the anisotropic dielectric responses in the deformed rubber-filler composites using the effective medium approximation (EMA). Our interpretation based on the EMA indicates that the large optical anisotropy in deformed rubbers is strongly linked to the internal filler network.