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Inquiry: How can nature and the human-made intersect?
Title: Chrysalis
Dimensions (h x w x l): 6 x 2 x 2 in
Date Completed: February 6, 2022
Idea: A chrysalis-inspired sculpture made using synthetic and organic polymers
Materials: , vinegar, hot glue, acrylic paint
Processes: Extracted chitosan from shrimp shells, extruded synthetic hot glue for form, used brown to enhance nature
INSPIRATION
CHRYSALIS OF THE BUTTERFLY
For this project, I wanted to try a different approach to my inquiry. To do this, my idea was to explore the idea of nature intersecting with the human-made in a more abstract manner. This approach can already be seen in my former work Carapace, which is a piece of design that takes inspiration from the skeletal structure of a turtle's carapace.
And with my current piece, I wanted to do something similar, but, instead, take inspiration from a butterfly's chrysalis. I was inspired by the chrysalis because it is a beautiful design of nature where the fascinating process of metamorphosis takes place.
The chrysalis or pupa stage of a butterfly's lifecycle is when a fully-grown caterpillar stops eating, finds a safe space, and transforms itself. They do this by spinning a little silk pad, to which they attach, and shed their skin, becoming a chrysalis. Chrysalises are most often found hanging upside down from tree branches. The caterpillar may seem to be resting, but inside the chrysalis, it is gradually undergoing a major transformation. For the first few days, a chrysalis is a bag full of nutrient-rich fluid. This is because the caterpillar's body is breaking down into a liquid form to rebuild itself as a butterfly.
The main biopolymer that makes up the chrysalis is chitin, the same compound that makes up insect exoskeletons and crustacean shells. Chitin is what makes the exterior of the chrysalis tough, shell-like, and resilient. These properties are necessary in order to contain the fluids inside the chrysalis and protect the vulnerable pupa from environmental pressures.
Conveniently, chitin is the second most abundant biopolymer on the planet, which makes it a viable source for bioplastics. Since chitin can be derived from shrimp and crab shells, it is also a readily accessible material. Chitosan, a deacetylated version of chitin, is a well-known substance in the world of eco-friendly alternatives to plastic.
PLANNING
My goal with my design was to take not take only structural, but also compositional inspiration from the chrysalis in order to fully emulate the natural properties in my design. To do this, my plan was to make a piece that looked like a chrysalis, but was also made up of the same materials that are in a chrysalis.
Given that a chrysalis is primarily composed of chitin, I decided to make my project out of chitosan bioplastic. To make this bioplastic, I had to get my hands on some chitosan. I was in luck because it turns out you can extract chitosan from shrimp shells if you use the right chemicals and processes. Basically, I had to make it from scratch.
I sketched out the basic form of a chrysalis from different perspectives, making sure to capture its 3D form and surface patterns.
Here, I sketched out two iterations of the chrysalis design. I noted down each iteration's physical characteristics, required materials and fabrication process to help me decide which one to go with.
This is the template I made for reference. The patterns displayed were inspired by those found on the exoskeleton of chrysalises as well as cells under a microscope.
PROCESS
CHITOSAN EXTRACTION & BIOPLASTIC SYNTHESIS
Before I started the extraction, I first processed the shrimp shells by washing them and then drying them in an oven for 2 hours at 100 C. After this, I ground the shrimp shells into a powder with a food processor.
To start off the extraction, I demineralized the shrimp shells by submerging it in a solution of hydrochloric acid for 3 hours. Subsequently, I strained, washed, bleached, and dried the shrimp shells.
For deproteinization, I submerged the shrimp shells in a sodium hydroxide (lye) solution at a temperature of 80 C for 6 hours. Once done, I repeated the intermediate cleaning stage.
At this point, the shrimp shells have become chitin.
Lastly, for deacetylation, the process that would transform the chitin into chitosan, I once again submerged the shrimp shells in a sodium hydroxide solution, but at a higher concentration for 5 hours at 115 C.
After one last cleaning, the transformation was complete. Chitosan was obtained. Now, the next step was to make the bioplastic.
To make this, I mixed a 1:10 mixture of chitosan to vinegar to make a gel, which I poured onto an oiled baking tray. Realizing waiting for it to solidify on its own would be too time-consuming, I baked this in the oven at 100 C until it solidified. At this point, the formerly transparent pale yellow chitosan gel had significantly darkened to become a brittle, thin sheet.
CHRYSALIS STRUCTURE
To make the "exoskeleton" that would hold the chitosan pieces in place, I used hot glue. I first drafted the pattern of the exoskeleton on my iPad and then drew the same design on a a glass bottle.
Then, I extruded hot glue along the lines I drew. To peel the glue exoskeleton, I filled the glass bottle with cold water, which quickly solidified the hot glue and made it easier to peel off. To make the clear, transparent glue blend better with the dark amber chitosan, I painted the exoskeleton a burnt umber brown.
To prepare the chitsoan pieces to be attached, I soaked them in water. I found that when dry, the pieces were quite brittle, but when soaked in water, they become very soft and malleable. I posit this is probably due to the material's biodegradability and solubility in water.
Finally, I attached the chitosan pieces by using the hot metal tip of the hot glue gun to melt and fuse the chitosan to the glue framework.
EXPERIMENTATION
I experimented in this piece by taking a more abstract approach to my inquiry. I aimed to explore the capabilities of new materials while illustrating how design and nature can work together. I also went through a new design process that required me to understand natural structures and processes beforehand.
I used unconventional materials, which in this case was shrimp shells. I used chemical processes to extract chitosan from the shrimp shells, and subsequently experimented with making a bioplastic made from chitosan and vinegar. The bioplastic had properties that was different from what I expected. When it was a gel, it had a lot more volume compared to after it had been solidified. Therefore, to make a sheet of chitosan plastic of adequate thickness, I had to overestimate the amount of gel to pour.
I also experimented with using hot glue to make an intricate patterned structure. I found that hot glue was a very suitable material because it was very malleable when hot, but it was surprisingly resilient yet flexible when solidified. It was also very light-weight, which made it possible for the chrysalis to hang from a strand of hot glue. Plus, it could also be reheated to attach things onto its surface. In making this hot glue exoskeleton, I went through three revisions of patterns (displayed below)
REFLECTION
This was one of my most challenging projects yet, but I had a lot of fun making it.
I learned a lot of new things about how materials behaved and the processes required to obtain them.
Many aspects of this project were challenging. Extracting the chitosan was pretty labor-intensive and technical. And since, I didn't have proper lab equipment, I had to improvise with glass jars and things I had at home.
Making the bioplastic was challenging as well. Before I poured the chitosan gel into a baking tray, I had poured it into petri dishes and shallow glass trays, but after I dried it, the plastic was stuck so firmly to the surface that it couldn't be removed. Only then did I revise and pour the gel into an oiled baking tray, from which it was relatively easier to remove the bioplastic from.
The art elements that were emphasized in these piece were texture, form, and material.
The chrysalis had varying textures — from the porous shiny chitosan plastic to the bumpy opaque hot glue. Ultimately this also affected how light refracted through the sculpture.
The form of the piece was also a unique one. It was inspired by various natural structures, which gave it a very organic look. It was a flat web of hot glue, which was then bent to make the chrysalis shape.
Last but not least, the material had a lot of emphasis because of its unconventionality and elaborate extraction process.
But ultimately, this piece shows a unity of nature and design, which is a human-driven process. Natural materials and muses were used to make something beautiful with the help of human ingenuity and design.
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