text: Most self-healing hydrogels rely on electrostatic attraction to spontaneously create new bonds. The electrostatic attraction can be masked using protonation of the polar functional groups. When the pH is raised the polar functional groups become deprotonated, freeing the polar functional group to react.
  Since the hydrogels rely on electrostatic attraction for self-healing, the process can be affected by electrostatic screening. The effects of a change in salinity can be modeled using the Gouy-Chapman-Stern theory Double Layer .
  * : Zeta Potential
  *: Salinity of solution
  *:  Distance between molecules, if the polar functional group is one molecule and an ion in solution is the other.
  To calculate the Gouy-Chapmanm potential, the salinity factor must be calculated. The expression given for the salinity factor is as follows:
  *: Charge of ion
  *: 1.6 * 10^{-19} C
  *: Number of ions per cubic meter
  *: Dielectric constant of solvent
  *:  8.85 * 10^{-12} C^2/(J*m), the permittivity of free space
  *: 1.38 * 10^{-23} m^2 kg/(s^2), Boltzmann Constant
  *: Temperature in kelvins
  These effects become important when considering the application of self-healing hydrogels to the medical field. They will be affected by the pH and salinity of blood.
  These effects also come into play during synthesis when trying to add large hydrophobes to a hydrophilic polymer backbone. A research group from the Istanbul Technical University has shown that large hydrophobes can be added by adding an electrolyte in a sufficient amount. During synthesis, the hydrophobes were held in micelles before attaching to the polymer backbone. By increasing the salinity of the solution, the micelles were able to grow and encompass more hydrophobes. If there are more hydrophobes in a micelle, then the solubility of the hydrophobe increases. The increase in the solubility lead to an increase in the formation of hydrogels with large hydrophobes.