Temperature-dependent Raman spectroscopic study of the nematic liquid crystal 4-n-pentyl-4'-cyanobiphenyl.
The spectral behaviors of 4-n-pentyl-4'-cyanobiphenyl (5 CB) have been studied by means of temperature-dependent Raman spectros-copy in the range between --70 and 70 degrees C. The nu(C identical with N) bands in the Raman spectra were found splitting below the transition temperature from the solid to the nematic liquid crystalline phase at approximately 24 degrees C, suggesting the existence of solid crystalline polymorphism. The interfacial structures of 5 CB on metal plate surfaces have been reexamined by surface-enhanced Raman scattering (SERS) at different temperatures. On Ag and Au, the asymmetric shapes of the nu(C identical with N) bands suggest that there should exist different binding schemes for 5 CB on metal surfaces. These asymmetric bands in the nu(C identical with N) stretching region were found to vary in changing temperature.
Kang
Dae Seung
DS
School of Electrical Engineering, Soongsil University, Seoul 156-743, Korea.
Kwon
Ki-Sun
KS
Kim
Sung Il
SI
Gong
Myoung-Seon
MS
Seo
Sung Seok A
SS
Noh
Tae Won
TW
Joo
Sang-Woo
SW
D001713:Biphenyl Compounds / Q000032:analysis / Q000737:chemistry*; D005818:Genetic Engineering / Q000379:methods*; D008859:Microscopy, Polarization; D009570:Nitriles / Q000032:analysis / Q000737:chemistry*; D011108:Polymers / Q000032:analysis / Q000737:chemistry*; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013696:Temperature
D001713:Biphenyl Compounds; D009570:Nitriles; D011108:Polymers; C422409:liquid crystal polymer; C433919:4-cyano-4'-pentylbiphenyl