8728
An integral asymmetric membrane was fabricated in a fast and one - step process by combining the self - assembly of an amphiphilic block copolymer ( PS - b - P4VP ) with nonsolvent - induced phase separation .
 Chemical: PS - b - P4VP
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: PS - b - P4VP