Polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) was applied to investigate Gibbs monolayers of ethylene glycol mono-n-dodecyl ether (EGDE), spontaneously adsorbed at the interface of air and aqueous EGDE subphase. Brewster angle microscopic images reveal that the EGDE monolayer Forms circular domains in a condensed state. The PM-IRRAS measurements reveal a v(as)(CH2) band at 2918.2 cm(-1) and a 6(CH2) band at 1469.2 cm(-1), indicating respectively the planar trans zigzag conformation and crystalline packing of the -(CH2)(11)- chain. The v(as)(C-O-C) mode gives a negative band, implying that the ether linkage preferentially stands up in the Gibbs monolayer. The Gibbs monolayer was successfully transferred onto solid substrates such as Au and CaF2, using the conventional Langmuir-Blodgett technique. Infrared transmission and reflection measurements of the transferred monolayer were applied to obtain the anisotropic complex refractive indexes. Using these indexes, the PM-IRRAS spectrum of the EGDE monolayer at the air/subphase interface was simulated and compared to the experimental one. It is concluded that the -(CH2)(11)- chain is tilted at 21degrees with respect to the surface normal and twisted at 56degrees on the aqueous subphase, The physical act of LB transfer onto solid substrates has caused reorientation of the -(CH2)(11)- chain and the ether linkage as well as deterioration of the chain conformational order.