18842
UV / ozone treatment offered a hydrophilic surface ( water contact angle ( theta ( water ) ) less than 10 degrees ) , reflecting the formation of a surface oxide layer with the maximum thickness of ca .
 Chemical: ozone; Chemical: oxide
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: ozone; Chemical: oxide