=manufacturing =materials
There are various reasons why one might want to switch to a new material, such as:
- less
toxicity or pollution
- slightly better performance
- less CO2
emission
- less oil or coal usage
- slightly lower cost
The least-common but
most-interesting purpose of new materials is enabling radically new types of
products. (Of course, newness is a matter of perspective: very different
systems for generating electricity all provide the same product to
consumers.) Some people have lots of resources, so every human need
generally already has some product that meets it. For most people, most of
the potential improvement is in making things that only the wealthy can
afford (such as houses) available to them as well; this is another way in
which novelty is subjective. For the same reason,
even useless novelties can be profitable, like how some people pay
extra for gold foil on food.
Anyway, here are a
few examples of potential new products with material-based novelty.
microLED displays
Instead of using liquid
crystals to selectively block light, why not just use lots of tiny LEDs?
That microLED approach
is feasible now for monochrome displays, but it's currently too hard to get
multiple colors from the same semiconductor substrate, and using a separate
little chip for every pixel is obviously impractical unless you're using
large LEDs to make an extremely large display.
That's why
OLEDs are used: it's
possible to print multiple organic semiconductors that produce
different colors in a pattern on a silicon substrate. However, those
organic LEDs have much worse efficiency and lifetimes than normal (ceramic)
ones. See that Wikipedia
article for more details on what people are doing to try to get
different colors without printing OLEDs.
electrospun yarn
For clothes, fibers that
have high tensile strength but can be bent easily are desirable. This
depends on both the inherent flexibility of the fibers, and on their
diameter.
PET has higher inherent flexibility than cellulose fiber,
but a cotton thread contains many small cellulose fibers, which makes it
more flexible overall. So, polyester clothing is stiff and uncomfortable
compared to cotton clothing. However, polyester clothing has much greater
durability, because the polyester fibers are continuous, while the cellulose
fibers can come apart.
If smaller-diameter fibers were used, soft
clothing could be made from PET or a similar polymer. And that's exactly
what microfiber is: particularly small PET fibers. That's used commercially
in textiles now.
But what if you want even smaller fibers? There is
an easy way to make very small fibers: electrospinning, where electrostatic
force expels fibers. The problem is that the resulting fibers are too thin
to work with: a few thousand electrospun fibers would need to be bundled to
match the thickness of silk. Even spinning them into yarn has been
impractical - but that is a solvable problem. Is there a good reason to
solve it? I'm not really sure, but clothing with electrospun nanofibers
might at least have some novelty value.
vacuum insulation
In space,
multilayer vacuum insulation can be 1000 times as effective per thickness as
typical insulation materials. Currently, vacuum insulation panels typically
use aluminized plastic, which leaks a very small amount of air when used on
Earth, and that small amount is still enough that expensive and somewhat
hazardous fillers are needed to maintain good insulation.
More-effective and cheaper vacuum insulation is theoretically possible. That
would be mostly useful for applications meeting all of the following
criteria:
- large
surface areas
- flexibility is not needed
- insulation is protected
from puncturing
- low thickness and low weight are valuable properties
Refrigerators and hot water tanks
are obvious applications. I've sometimes wondered whether vacuum insulation
could also be useful in clothing somehow. Obviously, rigidity, fragility,
and lack of porosity are undesirable attributes for clothing, but, for
example, a lightweight and very-insulated hat could still be situationally
valuable.
Vacuum-insulated glass is already being made commercially
on a small scale, but it's struggled to compete with triple-glazed glass.
That uses small beads of silica as separators for two glass panels with a
vacuum between them.
low-porosity concrete
Over
time, concrete develops cracks. Concrete is porous, so water can get into
the pores, expand when it freezes, and crack the concrete. Concrete has low
tensile strength and is brittle, so it can crack from thermal expansion
easily.
Concrete is porous because of the space taken by water during
curing, and in addition to letting water in, its porosity also greatly reduces its strength. This is why
superplasticizers can increase its strength: by reducing water needed for
flow, the ultimate porosity is reduced. This is an issue that much
can be done about, but the details are complex and beyond the scope of this
post. Anyway, concrete that has much higher strength (>20x typical concrete
strength) and doesn't crack so much is theoretically possible; the
disadvantage would be some combination of higher cost, reduced flowability,
and extra processing steps. Reduced porosity would also make concrete easier
to clean.
flow batteries
You can buy
vanadium flow batteries. They're sometimes used for battery backup systems.
Compared to lithium-ion batteries, they're somewhat more expensive, much
heavier, and somewhat less efficient, but they last for many more cycles.
Overall, flow batteries have fallen out of favor due to lithium-ion battery
improvements.
Flow batteries are the most promising system for
large-scale grid energy storage. Better flow batteries would enable higher
utilization of solar power. They also don't require a large scale; flow
battery grid energy storage could be distributed, providing backup power in
addition to electric power leveling.
Vanadium is too
expensive/uncommon to use in flow batteries for large-scale grid energy storage. The ion
combinations are limited and all of them have already been considered, so a
novel ion combination alone isn't a solution to the current issues. The main potential means of improving flow
batteries are better ion-exchange membranes and adding organic compounds
that form complexes with the metal ions. (Current research seems to be more
oriented towards using organic redox agents, which is a dead end
economically but good for generating publications.)
solid oxide fuel cells (SOFCs)
Currently, natural gas is burned to produce heat for steam methane
reforming. Solid oxide fuel cells operate in the temperature range used for
that, which means that their waste heat could directly replace natural gas
usage, so their electricity production would have an effective efficiency of
100%, rather than the ~60% of 3PRH CCGT plants.
Another potential
advantage of non-turbine electric generation systems is smaller minimum
scale. Gas turbines need to be large to have good efficiency: their
efficiency increases with size due to leakage around the edges and Reynolds
number effects, up to at least 100 MW.
Large thin layers of ceramic
without any cracks are expensive. That's the main reason solid-electrolyte
lithium batteries aren't practical. SOFCs are much closer to being viable
than solid-electrolyte lithium batteries, because:
- much higher
resistive losses are acceptable
- temperatures are higher, increasing
conductivity
- they typically run all the time, so cost and leakage are
less important
Currently, SOFC lifetimes being
too short, mostly because of cathode corrosion. SOFCs have been researched
extensively already, but the calibre of researchers applied to that topic
has been somewhat less than that applied to, say, nuclear weapon
development, so perhaps there's still hope. Personally, I think
ceria-carbonate SOFCs are somewhat interesting.
Incidentally, the
reason why using multiple dopants in ceria oxide conductors is useful is
because at high dopant concentration, multiple dopant atoms of the same type tend to form complexes with a
higher activation energy for oxide migration.
Recently, I was
thinking about SOFCs again, because there's been some new interest in CO2
utilization, by...running SOFCs backwards to make CO from CO2. So, if only
SOFCs were cheaper, instead of just converting methane to syngas, people
could convert methane to electricity at 60% efficiency, and then use that
electricity to convert CO2 to syngas at 60% efficiency. Amazing. Well, I
guess it makes about as much sense as turning ethanol into ethylene to make
renewable plastics, while also turning ethylene into ethanol because that's
cheaper than fermentation.
cryogenic aluminum
Ultrapure aluminum at low
temperatures has high electrical conductivity: at the boiling point of
hydrogen, its conductivity is >1000x that at room temperature. Aluminum
purification is cheap, and cryogenic aluminum could theoretically be used
for really high-performance electric motors or power lines, but cooling and
insulation for such low temperatures is too expensive.
So, the only
good application for cryogenic aluminum that comes to mind is MRI machines.
Yes, it would be hard for a new company or new technology to enter that
market at this point, but there are some theoretical advantages that
cryogenic aluminum could have over superconductors.
Hydrogen
liquefaction is currently fairly expensive. Improvements in magnetic
refrigeration could theoretically make it somewhat cheaper, so that's
another way that new materials could be relevant.
biodegradable plastics
This
isn't so much an application as an anti-application, but if biodegradable
plastics let people have beaches and forests without lots of plastic litter
on them, and let other people use plastic straws that would otherwise be
banned, that's sort of enabling things with new materials.
plastic walls
Themoplastics
are more expensive than steel, but have an association with trading
performance for cost becauses they have a lot of advantages in
manufacturing, and can reduce the labor and machinery required.
Walls
in buildings are made by:
1) nailing
drywall to a frame
2) applying joint compound to the drywall
3)
sanding the joint compound for a smooth surface, which makes hazardous dust
4) applying primer
5) painting
If the walls were plastic instead, then steps 2-4 could be skipped. Also, polymer walls would be lighter and thus easier to carry. Plastic walls would probably be mostly polypropylene, which certainly isn't a new material; the only new part would be significantly expanded low-cost production.
plastic beer bottles
One
reason plastic isn't used for beer bottles is that even a small amount of
oxygen ruins the flavor of beer. This was solved sometime before 2000, by
using an EVOH gas barrier layer. If you don't care about having any
transparency, an aluminized plastic layer also works.
However,
current beer production generally uses tunnel pasteurization, where the
bottles go through an oven hot enough to kill microorganisms. That
temperature would weaken PET enough that it couldn't handle the internal
pressure.
So, plastic beer bottles would require a cheap polymer with
good strength at moderately high temperatures, preferably something with
good gas barrier properties too. That would be a great material science
accomplishment, but I can't say I care much about this application.
foam flooring
I dislike PVC
flooring. It releases phthalates, which are toxic and smell bad.
I
don't like carpet very much, because it's hard to clean. Mitigating that
issue is why most carpet today has fluorosurfactants added to it, which are
toxic.
Cork is basically a natural foam flooring, and it works pretty
well. (Arguably, wood is a type of foam as well, but let's not get into
semantics.) EVA foam can be used on floors, but rather than a thin,
high-density layer as flooring, it's more common for EVA to be used as thick
soft interlocking tiles for exercise rooms and play areas for children.
Incidentally, while EVA isn't inherently hazardous at all, many
manufacturers of EVA foam flooring tiles added formamide - a toxic and
volatile compound - because it's cheap and apparently made the foam slightly
softer. I guess that's the level of civilization we have.
Creep could
be an issue if putting furniture on EVA foam flooring, so ionomer foam seems
better to me. Places like
dance studios and gymnasiums sometimes use a layer of higher-density ionomer
foam to make the floor a little bit softer. It just seems to me that some
sort of polymer foam could be used as a general-purpose flooring replacing
carpet, rather than niche situations where a particularly soft floor is
desired. Maybe this is an issue of fashion more than material availability.
nontoxic receipts
It's questionable whether
this should count as a new product, but I really hate BPA, and receipts are
a major source of exposure. The BPA-free ones use BPS instead, which is just
as bad. This is completely unnecessary but nobody who matters cares, despite
BPA and BPS being some of those hazardous chemicals that together are increasing
obesity rates, reducing sperm counts, lowering IQs, increasing cancer
occurrence, increasing diabetes incidence, and so on.
longer-lasting rubbers
Most
rubbers contain double bonds or ethers, either of which makes them
relatively susceptible to oxidation.
It's possible to use a
polyurethane containing hydrogenated hydroxyl-terminated polybutadiene,
which lasts about as long as polypropylene, but that's considerably more
expensive, about 6x the cost of regular polybutadiene. Part of this high
cost is due to patents.
recyclable tyres
Tires are typically
polybutadiene, crosslinked with sulfur (vulcanization), and filled with
carbon black. There are some disadvantages to this approach:
A) The
crosslinking process means the rubber can't be melted and reused afterwards.
B) Polybutadiene oxidizes relatively quickly.
C) The carbon black is
released as tires wear down. This is a major source of particulate
pollution.
Thermoplastic elastomers could theoretically be reused,
but current ones are more expensive and have too low a melting point, but
this is a solvable problem.
Rebound resilience is also very important
for tires, because it affects both efficiency and heating of the tires.
That's why polyurethane is used for solid tires but not pneumatic tires: it
lasts perhaps 4x as long as standard rubber, but it has higher losses from
bending. But there are some polyurethanes with even better rebound
resilience.
As for carbon black, it could be replaced by calcium
carbonate precipitated in certain ways, which would actually be slightly
cheaper and give slightly better performance, but nobody who matters cares.
GaN radios
Gallium nitride
is being used in some power electronics now. While it's currently
somewhat expensive, I expect it to be more-used than SiC for power electronics in the
long term, but people aren't really investing in it as much as they should. One advantage of GaN is that it can switch very quickly. Widely
available GaN could enable higher-frequency and higher-power WiFi-type
radio. Higher frequency would mean that radio dishes could be smaller for
the same spread. As for higher power, well, WiFi power is already limited
mainly by FCC regulations.