Ask A Scientist Materials Science Archive

  
name         Dina
location     AZ

Question -   What are the differences between neutral polymer and
polyelectrolyt?


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A neutral polymer is one that has no electrical charge or ionizable
groups such as polyethylene oxide, cellulose, sugar, polyvinyl alcohol, or
polystyrene. There are many other examples. Some neutral polymers are
water soluble, others are not.

A polyelectrolyte is a polymer that has an electrical charge. The
electrical charge (most frequently negative) usually makes such polymers
water soluble if the ionizable groups are neutralized. Many biological
polymers fall into this category. Synthetic polymers, for example,
polyacrylic acid fall into this class. There are also inorganic
polyelectrolytes like poly phosphates and poly silicates.

Vince Calder
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Most synthetic polymers are "neutral" polymers in that none of the 
chemical bonds in the repeating structure of the polymer are ionic. As 
such the bonds do not ionize in water or under an electric field. 
Polyelectrolytes on the other hand have, somewhere within the repeat unit 
of the polymer, a bond that will ionize in water (like a salt), or is able 
to release a small ion that can carry a charge.

Greg (Roberto Gregorious)
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