29380
The PPI measurements were correlated with solution viscosity ( measured by DLS using polystyrene nanospheres and ultrasonic shear rheology ) as a function of pH ( 4 - 9 ) and ionic strength ( 10 , 50 and 150mM ) .
 Chemical: polystyrene
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: polystyrene