16571
Poly ( lactic acid ) - block - poly ( ethylene glycol ) copolymers ( PLA - b - PEG ) featuring varying tacticities ( atactic , heterotactic , isotactic ) in the PLA block were synthesized and investigated for their micellar stability , degradation , and thermal properties .
 Chemical: Poly ( lactic acid ) - block - poly ( ethylene glycol ); Chemical: PLA - b - PEG; Chemical: PLA
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: Poly ( lactic acid ) - block - poly ( ethylene glycol ); Chemical: PLA - b - PEG; Chemical: PLA