The field of thermo- and pH-sensitive copolymers, with applications in controlled drug delivery, is enriched with the copolymer based on N-vinylcaprolactam and maleic acid (VCL-MAc) that is synthesized and characterized in this paper. Cloud point measurements and dynamic light scattering are used to characterize the phase transition of VCL-MAc copolymers with variable composition in aqueous solution. The lower critical solution temperature (LCST) increases when the maleic acid content in the copolymer rises. Also, the LCST strongly depends on the polymer concentrations and the pH of the aqueous solution. The influence of the pH, and as a result of the polyelectrolyte dissociation, on the macromolecular chains conformation is studied by viscometric measurements. An interplay between Coulombic, hydrophobic and hydrogen bonding interactions determines the conformation of the macromolecules in solution and also the phase separation of VCL-MAc copolymers.