BEH. 462/3.962J Molecular Principles of Biomaterials Spring 2003 o Brannon-Peppas paper analyzes Polyacrylates/polymethacrylates o In water pH 7.0 with 1=0.35 oX=0.8 pKa =6.0 o Vsp, 2=0.8 cm"/g M=75,000 g/mole Mc= 12,000 g/mole M=90g d2r=0.5 250 15o 200 900 g3o 1234587810111 PH of Swelling Medium 1o1112 pH。 f Swelling medium Fig 3. Theoretical swelling predictions at comparable ionic strength conditions for an anionic network with ()pKn=20(2)pK。=40(3pDK=60(4)pK=80.andstenghcondtlnsorananionicnetworkwith()=005 (5)pKa=10.0 (2)I=0.1,(3)I=0.25,(4)I=0.5,(5)I=0.75,(6)=1.0, and(7)I=20. Lecture 9-polyelectrolyte hydrogels 16of17      BEH.462/3.962J Molecular Principles of Biomaterials Spring 2003 Eqn 41  2  10− pKa  2  φ 2,s 2  vm,1     1− 2 Mc        φ 2,s   1/ 3 − 1   φ2,s     2 vm,1  10− pH +10− pKa     4Ivsp,2 M0 2   = ln(1 − φ2,s) + φ2,s + χφ2,s + φ2,r   vsp,2 Mc   M φ 2,r  2 φ2,r  o Brannon-Peppas paper analyzes Polyacrylates/polymethacrylates: o In water pH 7.0 with I = 0.35 o χ = 0.8 o pKa = 6.0 o vsp,2 = 0.8 cm3 /g o M = 75,000 g/mole o Mc = 12,000 g/mole o M0 = 90 g/mole o φ2,r = 0.5 Lecture 9 – polyelectrolyte hydrogels 16 of 17