14585
We prepared colloidal crystals by self - assembly of gold - coated silica nanospheres , and free - standing nanoporous membranes by sintering these colloidal crystals .
 Chemical: silica
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: silica