Temperature and pH sensitive copolymers

An amphiphilic block copolymer comprising at least three types of monomeric units, said three types of monomeric units comprising:

• a temperature-sensitive monomeric unit, wherein the temperature-sensitive monomeric unit imparts temperature-induced phase separation character to the amphiphilic block copolymer,
• a hydrophilic monomeric unit, wherein the hydrophilic monomeric unit has one or more polar functionalities, and
• a hydrophobic monomeric unit comprising at least one pH-sensitive moiety;
• wherein said hydrophobic monomeric unit is derived from a copolymerisable unsaturated fatty acid;
• wherein said unsaturated fatty acid imparts hydrophobic character to the amphiphilic block copolymer;
• wherein the fatty acid comprises 5 to 50 or more main chain carbon atoms;
• wherein the fatty acid comprises one carbon-carbon double bond (monounsaturated);
• and
• wherein the amphiphilic block copolymer exhibits a lower critical solution temperature (LCST) dependent on environmental pH.