Week 4

April 28, 2017

This week, we acquired sufficient materials to perform our first test of creating alginate hydrogels.

By mixing consumer sodium alginate with water, we created an aqueous solution of alginate. We mixed this with a solution of calcium chloride and agitated it to create a solution of aqueous sodium chloride and a precipitate of calcium alginate gel.

Figure 1: Materials

For every gram of sodium alginate, about 100 mL of water had to be used to dissolve the powder. A drop of red food coloring was used to dye the aqueous alginate so that when the gel formed after the reaction of 2% sodium alginate with 5% calcium chloride, it could be distinguished in the clear solution.

Figure 2: Calcium alginate hydrogels

After we were able to successfully create gels, we tested the amount of pressure required to burst gels of various sizes and different alginate concentrations. We found that more concentrated alginate solutions created bubbles that needed more force to burst, while larger bubbles were easier to burst.