Polymer and composition thereof

A thermosensitive polymer having a structure of formula (I-2),

• wherein
• R1 are identical or different and are each independently selected from C1-C12 alkyl, and the C1-C12 alkyl is optionally substituted with one or more substituents selected from the group consisting of halogen, hydroxy, alkoxy, haloalkoxy, cyano, amino and nitro;
• ring E is selected from phenyl;
• L are identical or different and are each independently selected from the group consisting of a bond, —C(O)—, —O—, —S—, —SO—, —SO2—, —C(O)O—, —NR′—, —C(O) NR′—, alkylene, alkenylene, alkynylene, heteroalkylene, cycloalkylene, heterocycloalkylene, arylene, heteroarylene and PEG, and the alkylene, alkenylene, alkynylene, heteroalkylene, cycloalkylene, heterocycloalkylene, arylene or heteroarylene is optionally substituted with one or more substituents selected from the group consisting of hydroxy, alkyl, alkoxy, haloalkyl, haloalkoxy, halogen, hydroxy, cyano, amino and nitro;
• A are identical or different and are each independently selected from a hydrophobic block,
• B are identical or different and are each independently selected from a hydrophilic block,
• wherein the hydrophilic block is selected from the group consisting of polyethylene glycol and polyvinylpyrrolidone, and the hydrophobic block is selected from the group consisting of a polyester and a polyamino acid;
• the hydrophobic block is selected from one of poly(DL-lactic acid), poly(D-lactic acid), poly(L-lactic acid), poly(DL-lactic acid-glycolic acid), poly(L-lactic acid-glycolic acid), poly(D-lactic acid-glycolic acid), poly-caprolactone, poly(DL-lactic acid-caprolactone), poly(L-lactic acid-caprolactone, poly(D-lactic acid-caprolactone), polyglycine, polyalanine, polyphenylalanine, polyglutamic acid, polylysine, polyornithine and polyarginine or a copolymer thereof;
• W are identical or different and are each independently selected from the group consisting of a bond, —O—, —S—, —SO—, —SO2—, —C(O)—, —C(O)O—, —NR′—, —C(O) NR′— and alkylene, and the alkylene is optionally substituted with one or more substituents selected from the group consisting of hydroxy, alkyl, alkoxy, haloalkyl, haloalkoxy, halogen, hydroxy, cyano, amino and nitro;
• R′ is selected from the group consisting of hydrogen, deuterium, hydroxy, alkyl, alkoxy, cycloalkyl, heterocyclyl, aryl and heteroaryl, and the alkyl, alkoxy, cycloalkyl, heterocyclyl, aryl or heteroaryl is optionally substituted with one or more substituents selected from the group consisting of halogen, hydroxy, oxo, nitro and cyano;
• m is selected from an integer from 5-150;
• n is selected from an integer from 5-300;
• a is selected from an integer from 2-11.