100 Nano-Stories: Why Are We Making Monolithic Aerogels?! 😡
Episode #35: Monolithic Aerogels Suck!
Preface! → ✨
Did I startle you, reader? Sorry for my angry introduction, but I don't understand why we create monolithic aerogels and expect everyone to use them in their daily lives!
If you’re confused, please check out my article where I explain the surface area of aerogels! It will give you some context on what I will speak about in this article!
Here is a brief overview of the article:
- The Surface Area can determine how much we can insulate.
- Volume can shrink or grow from the Surface Area / Volume Ratio (SA / V).
- SA / V ratio can be high or low.
- If SA / V ratio is low (3 : 1), it means that not a lot of fluid can make it to the center of the gel/object.
- If SA / V ratio is high (500 : 1), it means that fluid can be easily absorbed by the gel. This is why hydrophilic aerogel can absorb water easily.
Why Is Monolithic Aerogel Bad? → 🤷🏽♂️
Monolithic Aerogels are large (cm), homogeneous blocks of aerogel. Homogeneous means that the aerogel is in uniform, the composition of the aerogel is the same in every nook & cranny of the gel.
An example of a monolithic aerogel would look like this:
However, to make a piece of aerogel of this quality will take months to manufacture & market. Months!!!
The reason why is the silica network pores with diameters between 2 and 50 nanometers. The structure is so fragile and brittle that anything can shatter the aerogel during the phase of the sol-gel process, or during supercritical drying, considering the supercritical temperature and/or supercritical pressure.
A figure of the supercritical temperature & pressure in the aerogel would look like this:
But the biggest reason why monolithic aerogels suck is because of their Surface Area To Volume Ratio (SA / V ). Monolithic Aerogels can only insulate a certain amount of area because of the SA / V ratio.
Make Aerogels Thin! → 💡
But what if we increased the surface area and decreased the volume of the aerogel? This can decrease the time needed to manufacture aerogels, but can also thermally insulate a lot more area, despite having a low volume (thickness)!
An analogy to describe this idea would be similar to a leaf. A leaf’s objective is to collect sunlight, undergo photosynthesis, and produce energy.
However, if a leaf wants to absorb as much sunlight as possible, it would want to have a huge surface area, but not that much volume (thickness). That way, the entire leaf can have energy and absorb as much sunlight as possible! This is why a leaf has a huge surface area, but almost zero thickness! The leaf’s goal is to become a sunlight-eating monster!
Now, let’s apply the same concept to aerogels! If we can make aerogels (silica, polymer, carbon, graphene) with almost zero thickness, we can increase the amount they can thermally insulate! The thickness should only be about 3 centimeters thick (approximately over 1 inch of thickness). That way, the overall SA / V ratio can remain at a high number and make aerogel a true thermal-insulating machine! 😤
Closing Thoughts! → 💭
Well, this was an interesting conversation! You thought I was going to cuss, reader? 😏
But now you know about a new way to look at aerogels and how we can increase production to finally make enough of it for everyone to use in their homes, clothes, technologies, etc! And it’s all thanks to the SA /V Ratio!
See you tomorrow for some more Aerogel Chemistry! 🧠
Vocabulary! → 📓
Monolithic Aerogels → Large (cm), homogeneous blocks of aerogel.
Homogeneous → The aerogel is in uniform, the composition of the aerogel is the same everywhere in the material/object.
Surface Area → The uppermost layer of something, or the surface of the object, and how much space (area) the object occupies.
Volume → The space that a 3-dimensional object occupies.
Previous “100 Nano-Stories!” → 🔖
© 2021 by Carlos Manuel Jarquin Sanchez. All Rights Reserved.
