9661
The model was fabricated using a dual photochemical approach , where poly ( methyl methacrylate ) ( PMMA ) thin films were cross - linked by a photoactive benzophenone monolayer and blended cross - linking agent .
 Chemical: poly ( methyl methacrylate ); Chemical: PMMA; Chemical: benzophenone
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: poly ( methyl methacrylate ); Chemical: PMMA; Chemical: benzophenone