12354
Although experimental and theoretical studies have addressed the question of the wetting properties of graphene , the actual value of the contact angle of water on an isolated graphene monolayer remains unknown .
 Chemical: graphene; Chemical: graphene
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: graphene; Chemical: graphene