27173
In this paper , we describe a systematic investigation of factors that affect the self - seeding behavior of PFS block copolymer micelle fragments .
 Chemical: PFS
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: PFS 
Answer:
 Chemical: PFS