1. Idea

During brainstorming for ideas we learned that is was important for our biomaterial to not easily catch on fire since me needed to laser cut it. We also found the idea of a transparent bioplastic given stability by a colorful mesh inside quite interesting. So we started looking into different materials that would show the right consistency, transparency, color and heat resistance. We found that sodium alginate mixed with pigment and different amounts of glycerin could be suitable for building the mesh base. For filling the mesh and creating an even and transparent material agar agar seemed promising.

We set our experiment up in the following way:

First we would apply a sodium alginate gel in a mesh form using a syringe, cook up the agar agar in water, then pour the mix over the mesh and let it cool and dry for a week.

2. Process – Alginate Mesh

For the alginate mesh we used:

• 5g sodium alginate 

• 0.53g sandelwood pigment

• 9g 99% glycerin 

• 10g calcium chloride 

• 1g potassium sorbate

• 450 ml distilled water

First we mixed a gel out of sodium alginate, glycerin, potassium sorbate, pigment and 150 ml distilled water using a blender. The pale red gel then had to rest for an hour for air bubbles to escape. 

After the waiting period we filled the alginate gel in a syringe and applied thin strings into a calcium chloride bath. We did this to solidify the strings. When liquid/ gel alginate touches the calcium bath, it swaps sodium for calcium ions. Because calcium can hold two chains at once, it instantly zips the liquid together into solid, elastic threads.

We let the mesh bath in the calcium solution for 10 minutes. Afterwards we retrieved it and put it on paper towels to dry since the agar agar connects better to alginate when dry.

3. Process – Agar Plate

For our agar agar plate we used:

• 12g agar agar 

• 4g 99% glycerin

• 0.63g potassium sorbate 

• 220 ml distilled water 

Opposite to the alginate mesh this process didn't take much time. We stirred together all the ingredients in a cooking pot using a whisk and then placed it on the stove to boil it. When processing agar agar it is important to mix it in cold water before cooking it. We then brought the mix to boil and stirred it for 2 minutes. Then we took it off the stove and let it cool down a bit for 30 seconds. We proceeded to pour it in a metal mould and spread it out to an about 6mm thick layer. 

For now we let the alginate mash and agar agar plate dry separately because we wanted to see how the materials act while drying.

4. First Experiment

This is how we left the first experiment to dry.

5. Result of the First Experiment

After two weeks we checked on our biomaterial for the first time. We could tell that:

• the agar agar plate had shrunken in thickness significantly to 0.5mm

• it had turned out to be an even solid but flexible plate 

• it showed a good transparency with a small yellow tint 

• after retrieving it from the metal form it started to warp

• the alginate strings had lost water and were thinner, darker and not really flexible anymore

6. Second Experiment

We wondered how to prevent the plate form warping and came up with the idea to apply the mesh in a certain way that it wouldn't warp as easily. After some research we decided to try it with two versions: one triangle  and one spider net mesh. We chose these shapes since they are very stable. When drying the material looses water and shrinks. Since it doesn't dry equally fast on the inside as it does on the surface it starts to shrink faster on some parts than others. The stable shape pf the mesh is supposed to withstand that uneven pulling together of the material. 

This time we combined both parts of our material and poured the boiled agar agar mix onto the alginate mesh. Since it had reduced in height significantly we calculated how much agar agar we needed to receive a 3mm plate in the end. This led us to cooking 4.5 liters of agar agar solution, since the last plate had shrunken to 1/12 in size.

7. Result of the Second Experiment

Our calculation turned out to be incorrect since even after several weeks the plate was still way too thick. It showed multiple centimeters in height and started to mildew.

8. Final Experiment

For our last experiment we did three different versions and changed some parameters:

• 10% of dry mass weight for potassium sorbate instead of 4%

• half the amount of glycerin in the agar agar plate

• triangle shape mesh for all three versions

• two smaller versions with different amounts of agar agar poured on top of alginate mesh

• one bigger version with a layer of agar agar, alginate mesh on top and a topping layer of agar agar

We were positive that at least one of the plates would turn out to be fitting since we couldn't exactly tell how much the biomaterial shrinks with different sizes.

9. Result of the Final Experiment

Sadly after one week our materials (and many others) showed a lot of mold and a strong unpleasant smell.  

The layered bigger plate was too thick but the smaller versions seemed to have the right thickness. But because they were also moldy and had bent none of the experiments truly were successful. 

We still chose to use one of the smaller versions that had bent less for laser cutting. We cut the edges, cleaned it with alcohol and flattened it using weights.

10. Laser Cutting & Final Production

We manged to retrieve one piece each for our ELEMENTS projects morphis, trinexus and spina. These pieces were all stable but the material wasn't very suitable for smaller parts like sharp edges oder thin bars. Also due the heating up during the lasering process the agar agar turned dark and less transparent so you couldn't see the alginate mesh very well anymore.