APS & TEMED in acid gels

Steven Cohen sbc4 at PO.CWRU.EDU
Wed Jan 22 20:37:11 EST 1997





This does not make sense to me either. Perhaps the kinetics of the
polymerization will be increased, but it is the amount of Bis-Acrylamide and
total Acrylamide concentration  that controls the quantity of cross-linking
which controls the porosity of the gel. Just like other catalysts, APS and
TEMED do not effect the final product but the speed in which equalibrium is
reached.



>>
>>If you can the amounts of APS and TEMED, you will change the kinetics of 
>>gelation (great, that's what you want).
>
>Agreed.  You can also control kinetics by changing the temperature.
>
>>  You will also change the porosity of 
>>the gel - the relative amount of cross-linking.
>
>Is this really true?  I was under the impression that the porosity
>was governed by the % acrylamide and by the ratio of acrylamide/bis
>(or other cross-linker).  The concentration of TEMED and/or persulphate
>shouldn't have any effect unless they become limiting - so that the
>gel fails to polymerise completely no matter how long it is left.
>Since they only catalyse the polymerisation of the acrylamide monomer
>they play no real role in the eventual structure of the gel.
>	Can someone correct or confirm my assumption?




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