The study of adsorbates physical chemistry on crystalline polymer surfaces is described in this thesis for the first time. In this work, is presented the interaction of water (adsorbate) with the ferroelectric surface of the copolymer poly(vinylidene fluoride) with trifluoroethylene. For more than 20 years adsorbates interactions have concentrated on the studies of adsorbates on metal, oxide or semiconducting material surfaces. Advances in preparing crystalline polymer substrate surfaces, compatible with ultra high vacuum techniques, makes this current novel effort possible. Given the increasingly ubiquitous presence of polymers and their applications in all venues of modern day life, such studies are essential. This will be among the first serious fundamental studies of the surface chemistry of a polymer, possible because of the combination of spectroscopies we can bring to bear on the problem together with the fact that it can be fabricated crystalline polymer thin films as substrates for molecular adsorption studies.