12308
We engineered specific microfluidic devices based on the pervaporation of water through a PDMS membrane , to formulate continuous and steady concentration gradients of a binary aqueous molecular mixture at the nanolitre scale .
 Chemical: PDMS
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