Jump to main content
Jump to site search
PLANNED MAINTENANCE Close the message box

Scheduled maintenance work on Wednesday 22nd May 2019 from 11:00 AM to 1:00 PM (GMT).

During this time our website performance may be temporarily affected. We apologise for any inconvenience this might cause and thank you for your patience.


Issue 26, 2012
Previous Article Next Article

Ion electrodiffusion governs silk electrogelation

Author affiliations

Abstract

Silk electrogelation involves the transition of an aqueous silk fibroin solution to a gel state (E-gel) in the presence of an electric current. The process is based on local pH changes as a result of water electrolysis – generating H+ and OH ions at the (+) and (−) electrodes, respectively. Silk fibroin has a pI = 4.2 and when local pH < pI, E-gel forms. An experimental system was constructed that allowed the measurement of E-gel growth and pH distribution for an applied current. To explain the observed rectangular pH profile of pHgel ≈ 4 surrounded by pHsilk-solution ≈ 10, a finite-element ion electrodiffusion model was developed. The model relies on electrodiffusion of the generated H+ and OH ions. Initially, inputs into the model were the measured E-gel and voltage curves. The governing ion electrodiffusion equations were solved and the calculated pH matched the experimental pH profile, indicating that ion electrodiffusion dictates local pH changes and E-gel growth. Furthermore, the model predicted the constant currents (2 mA and 3 mA) necessary for two hypothetical E-gel growth curves and these results were then validated experimentally. The model thus shows how ion electrodiffusion governs the electrogelation process and also provides predictable outcomes for fundamental and practical E-gel applications.

Graphical abstract: Ion electrodiffusion governs silk electrogelation

Back to tab navigation

Publication details

The article was received on 03 Apr 2012, accepted on 08 May 2012 and first published on 28 May 2012


Article type: Paper
DOI: 10.1039/C2SM25783A
Soft Matter, 2012,8, 6897-6905

  •   Request permissions

    Ion electrodiffusion governs silk electrogelation

    N. Kojic, M. J. Panzer, G. G. Leisk, W. K. Raja, M. Kojic and D. L. Kaplan, Soft Matter, 2012, 8, 6897
    DOI: 10.1039/C2SM25783A

Search articles by author

Spotlight

Advertisements