Ashraf Alam
Jannat Nabonee
Mohammad Bazal
John Cordero
City College of New York
English 21007
Professor. Sara Jacobson
April 28, 2023
Abstract
Novelty is not hard to find; however, identifying products with novelty and practical applications is a difficult task. In this paper, our group will discuss the applications of aerogel, specifically silica aerogel, to be used as iPhone cases. Application of such methods is not common/new: the cost to make silica aerogel padding costs a lot, and it does not have a wide range of practical uses. The current product is mainly used for camping and outdoor activities. For these limitations, our group has created an iPhone case made from silica aerogel that is used for practical uses and costs less to produce.
Background Inventions
The average American drops their phone at least four times every week, meaning that every American has a 0.57% chance of dropping their phone in one day (New York Post, 2019). To minimize such ordeals, many companies have tried to create phone cases to mitigate these effects; however, with enough time and stress on the casing, originally made from rubber, silicone, wood, and other materials, along with case usage, the device will eventually crack/break. Well-known companies such as Mous filmed how well their casing fared in their ability to withstand large drops, smashes, et cetera with their case (Airoshock™ US, n.d.). It is composed AiroShock, a material that has energy-absorbing properties via cross-linking polymer chains (“Limitless possibilities SOLIDWORKS,” n.d.). Another well-known company, Casetify, uses a mixture of materials: biopolymers, bamboo, and starch (“CASETiFY,” n.d.). Both companies have reputable casings; however, both have limitations in the materials used for their cases: they can become damaged or fail due to long-term stressors. This notion leads one back to the same problem of using phone cases lest the user has no fear of breaking their phones.
Silica Aerogel
When looking into the origin of aerogel, Samuel Kistler was the first to invent it in 1931 (Ayers, n.d.). Since then, it has picked up an interest for its various properties, being able to trap air molecules because of its low density and high porosity, referring to the amount of space/void in materials. This, in turn, makes it a great insulator of heat and sound; in comparison to conventional insulation materials like fiberglass, which can be up to 39 times more effective (“What is aerogel,” n.d.). Aerogel comes in many different shapes, colors, sizes, et cetera, created from various materials such as metal oxides, organic polymers, and so on (“What is aerogel,” n.d.). Aerogel refers to a general type of aerogel; however, this paper will discuss silica aerogel, the most used aerogel, typically created from silica gel, hence the name (“Silica aerogel,”n.d.). The silica gel is dried and typically has about 50% of its liquid extracted. Depending on the method used for drying, a certain percentage of the original volume of the gel will be kept, creating silica aerogel (“Silica aerogel,” n.d.). Silica aerogel can hold up to 2000 times its weight, keeping the applied force coated throughout its surface preventing the gel from snapping/fragmenting (“Strong and flexible aerogels,” n.d.). By norm, silica aerogel is typically used in lasers, fridges, waste management, optics, electronic devices, et cetera (Gurav et al., 2010).
Void for SilicaAerogel
An already existing company, Cold Gear Case, produces iPhone bags insulated by silica aerogel. These iPhone bags, acting as iPhone cases, break the norm of weak/decaying iPhone cases mentioned above and are practically indestructible. Using these iPhone bags, the iPhone can survive in extreme heat and cold, is water-resistant, waterproof, and can float, et cetera (“The indestructible floating phone case,” n.d.). This iPhone bag, however, is intended for the outdoors, which directly pertains to camping/hiking/living in extreme weather, temperatures, and climates. For this reason, this paper will argue that aerogel, especially silica aerogel, can be created with an alternatively low-cost method other than the one used by Cold Gear Case: for the casing and insulation of iPhones and other devices to make it more commercially available for everyday use. Instead of the bag casing for the iPhone, a standard iPhone case could be created without losing the benefits of the beforementioned specs of the Cold Gear Case.
Shows the silica aerogel padding bag from Cold Gear Case and the iPhone 14 to compare it in size and dimension.
Note.This figure was taken from Thermal phone case by case gear. Garage Grown Gear (n.d.)
Ineffective Materials
The average iPhone case consists of polycarbonate or thermoplastic polyurethane, two commonly used plastics for their high young modulus value and stress-strain ratio: the higher the young modulus, the greater the resistance of the material against deformities under compressive or tensive stress (“PC,” n.d.; Lee et al., 2019). However, on average, Americans buy around 27 iPhone cases because of case failure, most of which are not recyclable (Ankarlid, 2022). In 2019, around 645 tons of plastic waste from phone cases alone were recorded (Ankarlid, 2022). Although big brand names like Casetify and Mous promote biodegradable phone cases, they are not excused from creating large quantities of waste from customers having to repeatedly buy newer phone cases. In such cases, silica aerogel would fill in that gap of protecting and maintaining functionality over time and stop the need to replace a new phone case every few years or so. As a beforementioned brand, Cold Gear Case newly implemented their phone bag, treated as a phone case with silica aerogel; however, their phone case is typically made for outdoor experiences and not intended to be used casually. This aerogel derivative case manages to correct the limitations of previous cases by implementing all the prior features while still allowing the average person to reap all the protective benefits.
Implementation of New Modal, Materials, and Case
Silica Aerogel is created by drying about 50% of a silica gel, leaving 90% of its total volume. The process by which this happens, supercritical drying, yields the best results, comprising higher pore concentrations and larger surface areas compared to ambient drying or other less effective yielding methods (Şahin et al., 2017; Błaszczyński et al., 2023). Supercritical drying refers to extracting solvent from the pores by using supercritical fluids, a temperature at which matter can exist as a gas and liquid (Şahin et al., 2017). However, Guo, et al. (2021) has concluded that ambient pressure-dried, different from ambient drying, yields 56% faster production times. Zhu et al. (2018) agree with such claims, reporting that surface area lost due to corrosion can be avoided through ambient pressure-drying, which yields a moderate pore volume. Silica Aerogel on its own is extremely tough, as evident from the details; however, by adding different metals and oxides, otherwise known as crosslinked silica aerogel, or x-aerogel, one can create an even stronger material with a higher stress-strain ratio than standardized silica aerogel while keeping its other properties (“Strong and flexible aerogels,” n.d.). With these two new novel implications of ambient pressure-drying and x-aerogels, it is possible to create a commercial, casual iPhone case that far exceeds the limitations of polycarbonate or thermoplastic-polyurethane/any other industry-regulated plastic products used phone cases while still having the benefits of a Cold Gear Case bag. This product will be similar in nature to the Cold Gear Case bag; however, two silica aerogel paddings will be encased between two biodegradable plastic cases, made from thermoplastic polyurethane, clipped on by a magnetic clip, and one silica aerogel padding between each plastic casing. Objectively, this is the best design for consumer use because it allows the user to remove the plastic casing, if damaged, and replace it while keeping the silica aerogel padding, which would prevent the whole case from being thrown out and contributing to pollution. This design will promote the recycling of the aerogel padding and reduce the overall waste created by phone cases.
Shows silica aerogel held from a hand.
Note. This image was taken from Silica aerogel. Aerogelorg RSS (n.d.).
Shows the stress and strain of normal/native silica aerogel to silica x-aerogel. Both the stress and young modulus value are higher as shown by the graphs.
Note. This graph was taken from Strong and flexible aerogels. Aerogelorg RSS. (n.d.).
Shows the compressive tests for various materials. X-aerogel sample one and two are comparatively higher than steel and aluminum.
Note. This graph was taken fromStrong and flexible aerogels. Aerogelorg RSS. (n.d.).
Shows the side, corner, and top view of our project’s modal. The black blocks are plastic casings, the green dots are magnetic clips, and the red blocks are silica aerogel padding.
Note. This figure was hand drawn.
Shows the yielded product of silica aerogel, on the left, from supercritical drying compared to silica aerogel, on the right, that has been ambient dried. The left silica aerogel has larger surface area, and is a higher quality yield compared to the right aerogel.
Shows the process of supercritical drying. CO2 is supplied from a tank into a pump, where a valve releases it into a pressurized vessel. The CO2 is then mixed with the solvent. This process yields higher pore volumes; however, is most costly.
Note. Both figures 4 and 5 were taken from Şahin et al., 2017
Costs and Time
The price to get a thermoplastic polyurethane film would depend on the thickness and length of that film. The average thickness used in commercial-grade phone cases is 0.3 to 1 mm, meaning it would cost around ten to fifty American dollars. With a 3D printer, the average time to print one plastic phone case would be a couple of hours, one to two days at most: the total time would be at least a day to print both plastic cases (Stone, 2022). Aerogel, in general, can come in three different forms: monoliths, powders, and films (Moheman et al., 2021). The film/mats would be the most sensible approach to use as insulation. A strip of silica aerogel film costs around five to 100 US dollars based on the quality, thickness, and producer. Since x-aerogel is fairly new and still being tested, obtaining them would be difficult, and recreating them from scratch would challenge an even harder/more costly task (Mandll et al., 2019). It would be cheaper to buy standard silica aerogel, commonly used in modern technology, silica aerogel films/mats for padding until further research allows it. Assuming and taking the average cost and time, it would take around 40-50 dollars to produce one phone case, two thermoplastic polyurethane casings, and two silica aerogel paddings. This estimate may change based on the dimensions of the phone; the quality of materials.
References
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Ayers, M. (n.d.). Part 1: Samuel Kistler, inventor of aerogel. Aerogelorg RSS. http://www.aerog
Błaszczyński, T., Ślosarczyk, A., & Morawski, M. (2013). Synthesis of silica aerogel by
supercritical drying method. Procedia Engineering. https://www.sciencedirect.com/scienc
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CASETiFY. (n.d.). https://www.casetify.com/compostable-case-
faq#:~:text=1.,%2C%20starch%2C%20and%20bamboo).
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Gurav, J. L., Jung, I.-K., Park, H.-H., Kang, E. S., & Nadargi, D. Y. (2010) Silica aerogel: Synthesis and applications. Journal of Nanomaterials. https://www.hindawi.com/journals/jnm/2010/409310/
Lee, H., Eom, R.-i, & Lee, Y. (2019). Evaluation of the mechanical properties of porous thermoplastic polyurethane obtained by 3D printing for Protective Gear. Advances in Materials Science and Engineering. https://www.hindawi.com/journals/amse/2019/5838361/
Limitless possibilities SOLIDWORKS. (n.d.). https://www.solidworks.com/sites/default/files/201
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New York Post. (2019). Americans drop their phones at least four times a week. New York Post.
https://nypost.com/2019/11/15/americans drop their phones at least four-times-a-week//
PC. Designerdata. (n.d.). https://designerdata.nl/materials/plastics/thermo-plastics/polycarbonate
Şahin, İ., Özbakır, Y., İnönü, Z., Ulker, Z., & Erkey, C. (2017). Kinetics of supercritical drying of Gels. Gels (Basel, Switzerland). https://www.ncbi.nlm.nih.gov/pmc articles/PMC6318630/#:~:text=Supercritical%20drying%20which%20can%20be,for%20drying%20the%20wet%20gels.
Silica aerogel. Aerogelorg RSS. (n.d.). http://www.aerogel.org/?p=16
Stone, W. (2022). How long does it take to 3D print a phone case? This long! RSS. https://www.3dprintingspot.com/post/how long does it take to- 3d print a phone case this l ng
Strong and flexible aerogels. Aerogelorg RSS. (n.d.). http://www.aerogel.org/?p=1058#:~:text=Although%20it’s%20true%20that%20a,might%20not%20be%20very%20much.
The indestructible floating phone case. Cold Case Gear. (n.d.). https://coldcasegear.com/
Thermal phone case by case gear. Garage Grown Gear (n.d.). https://www.garagegrowngear.com/products/thermal-phone-case-by-cold-case-gear
What is aerogel? Aerogelorg RSS. (n.d.). http://www.aerogel.org/?p=3
Zhu, L., Wang, Y., Cui, S., Yang, F., Nie, Z., Li, Q., & Wei, Q. (2018). Preparation of silica aerogels by ambient pressure drying without causing equipment corrosion. Molecules (Basel, Switzerland). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6222790/
Group Presentation
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