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Three PEMs are considered : Nafion , sulfonated polystyrene ( sPS ) that forms the hydrophilic subphase of segregated sPS - polyolefin block copolymers , and random sPS - polyethylene copolymer .
 Chemical: Nafion; Chemical: sulfonated polystyrene; Chemical: sPS; Chemical: sPS; Chemical: polyolefin; Chemical: sPS; Chemical: polyethylene
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: Nafion; Chemical: sulfonated polystyrene; Chemical: sPS; Chemical: sPS; Chemical: polyolefin; Chemical: sPS; Chemical: polyethylene