Six f-block salts from the lanthanide series form complexes with poly(vinyl amine) and increase the glass-transition temperature of the polymer. Results for poly(vinylamine) complexes with EuCl3(H2O)(6) and TbCl3(H2O)(6) surpass those for d(7) cobalt complexes that were studied previously. The glass-transition temperature increases by 49 degrees C per mol % Eu3+ and 50 degrees C per mol % Tb3+, up to 2 mol % of the f-block cat;ions. At 5 mol % Eu3+, T-g is slightly higher than 250 degrees C with no visual evidence of thermal degradation of either component in the complex. This corresponds to a T-g enhancement of almost 200 degrees C with respect to the undiluted polymer. The increases in T-g for these lanthanide complexes with poly(vinylamine) obey the following trend: TbCl3 approximate to EuCl3 > SmCl3 > ErCl3 > GdCl3 > Gd(CH3COO)(3) up to 2 mol % of the f-block cation. With the exception of Gd(CH3COO)(3), which contains different anionic ligands than all. of the other trichlorides, this trend correlates inversely with the highest dehydration/dehydrochlorination temperature of each undiluted lanthanide salt, as measured via calorimetry above the melting point and verified by thermogravimetry. Waters of hydration and amino sidegroups undergo ligand substitution in the coordination sphere of the lanthanides. Since lanthanide cations are classified as hard acids, it is not unreasonable that they form complexes with the nitrogen lone pair in the amino sidegroup of the polymer, which is classified as a hard base. Micro-clustering of several amino side groups reduces chain mobility significantly in the vicinity of each metal center, produces coordination crosslinks, and increases T-g. Complementary solution studies reveal that hydrogels form with swelling ratios between 20 and 50 at Eu3+ mole fractions between 0.01 and 0.05 with respect to poly(vinylamine). Infrared spectroscopic observations suggest that the amino nitrogen lone pair in poly(vinylamine) interacts with these lanthanide metal centers.