Here we present a combined analytical study of a homological series of poly(2-(dimethylamino)-ethyl methacrylate)s (DMAEMA) and their corresponding with methyl iodide quaternized versions poly[2-(methacryloyloxy) ethyl] trimethyl-ammonium iodide]s (QDMAEMA) in a wide range of molar masses (~7 to ~300kDa) and low dispersities (~1.1 to ~1.3). The polymers were studied predominantly in 0.2MNaCl in water at T=20.0°C applying mutually reinforcing's set of hydrodynamic methods, such as, viscometry, analytical ultracentrifugation, dynamic light scattering, isothermal diffusion and size exclusion chromatography. The manuscript provide compulsory discussions on the evaluation of physically sound values of the molar masses, hydrodynamic sizes and conformations of the macromolecules in solution. Special attention is paid to the investigation of ion-specific interactions and their influence on the hydrodynamic and molecular characteristics. The conformation of polymer chains in solution was validatedvia the classical scaling equations showing θ-conditions – [η]=0.055M^0.47±0.04;s=0.006M^0.50±0.02;D=1200M^-0.50±0.02 for the initial DMAEMAs polymer chains and thermodynamically good ones for the quaternized macromolecules characterized by [η]=0.002M^0.80±0.04;s=0.0133M^0.45±0.02;D=1665M^{−0.55±0.02}. The equilibrium rigidity was found to be visibly influenced by the overall electrostatic interactions and the presence of closely associated iodine ions to the quaternized polymer chains giving A=4.4nm in comparison to A=2.4nm for the initial macromolecules.