The invention provides for novel thermo-responsive polymers and compositions comprising the same. In some embodiments, the polymers are water soluble, pH-degradable and have tunable lower critical solution temperatures. Other aspects of the invention include micelles and gels comprising the thermo-responsive polymers and derivatives thereof, as well as methods of delivering therapeutic agents comprising administering a biodegradable gel or micelle comprising a polyacetal compound cross-linked with a linker.