The effect of temperature and buffer solutions with different pH (often used in biomedical applications) on the behavior of POEGMA brush coatings, synthesized without incorporated functional groups, was for the first time studied in details using water contact angle (CA) measurements and atomic force microscopy (AFM). Thermal response of grafted brush-coatings based on poly(oligo(ethylene glycol) methacrylate)s (POEGMA)s is driven by lower critical solution temperature (LCST) phenomenon. Obtained CA and AFM results suggest strong impact of the buffer solutions on the values of LCST transition and contact angle ranges, as well as on coatings morphology. In turn, ellipsometry data reflect penetration of salt ions from buffer solutions into brush-coatings. In contrast to “typical” behavior of POEGMA coatings in water, different mechanisms available below LCST in the buffer solutions destroy hydrated layers surrounding POEGMA macromolecules leading to their collapse.