11831
We found that PDA films are highly hydrated under wet conditions because of their porous membrane - like nanostructures and hydrophilic functional groups .
 Chemical: PDA
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: PDA 
Answer:
 Chemical: PDA