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PDMS surface modifications studied include primary amine groups , carboxylic acid groups , and neutral polymer surfaces .
 Chemical: PDMS; Chemical: primary amine; Chemical: carboxylic acid
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: PDMS; Chemical: primary amine; Chemical: carboxylic acid