Advanced materials everyone can afford including Nature
[Music]
my name is marcus buehler i am the
mcafee professor of engineering at mit
and my goal is to create bio-inspired
sustainability
we want to be able to create almost any
function out of almost any material by
using
nature’s hierarchical design approach
that reassembles molecules to create
functional diversity out of universal
building blocks
this is a powerful paradigm that i
believe will change the way we construct
as engineers the way we
design as engineers and the way we can
actually address the sustainability
challenges that we’re facing today
the world in 30 years is going to look
very different than the world today
we’ll have a changing climate
and additional constraints on the
environment we have higher population
densities we have less resources likely
and we’re going to have more waste and
this waste is going to include more
chemical diversity and
maybe even nanostructures we also have
different climate conditions
we have changes in temperature and
humidity that we’ll have to deal with
on the other hand we have a lot of hope
and opportunities ahead of us
we expect major breakthroughs in
nanotechnology
we can assemble materials atom by atom
we can discern transformations using the
existing building blocks in waste or in
existing materials to designer materials
that are made
atom by atom and constructed molecule by
molecule with tailored
desirable functions we’ll also be able
to engineer living organisms
biomaterials and look to nature for
inspiration we can work with nature
instead of against nature and create new
solutions for humanity
biomass waste and advanced materials are
inextricably linked and provide major
opportunities for the future
biomass for instance is a renewable
material it’s a carbon sink
and it’s easily available today already
at 1 billion tons per year in the united
states
we can then use these biomass based
materials to create carbon materials
nanomaterials composites
or even energy materials such as
electrodes and batteries
the paradigm we’re using is called
meteoromics the design material is atom
by atom
just like nature constructs materials
with advanced function from virtually
any resource
we can use the meteorological approach
to build materials molecule by molecule
with advanced function
to do this we look at materials at
multiple levels from the nano scale all
the way to the macro scale
at the nano nanoscale we’re dealing with
chemistry the assembly of molecules
how molecules form micro nanostructures
and mesoscale structures
which then in turn assemble into
hierarchical levels
all the way up to the macro level that
we can see with our eyes
this multiscale structuring is really
the hallmark by which
biological living organisms are
constructed and their exemplary
manifestations of
biorefineries nature is able to
refine materials reconstruct reorganize
materials
from virtually any source we think about
spiders for instance spiders are amazing
species they build spider webs
in two dimensions and three dimensions
they create
very complex material constructions for
various purposes such as protecting
their prey
protecting their young their offspring
and these silk materials are all made
from what we call proteins or amino
acids
another kinds of protein materials are
those found in the ocean such as the
glues in marine materials like muscles
they create incredible glue materials
that work underwater in sea water under
virtually any conditions
we also find biological materials made
from proteins in the human body
such as in our cells in our nerve cells
in our skin cells to organ cells
virtually anywhere we are made from
proteins proteins are
nature’s choice to build materials and
proteins are really constructed from
very simple chemical building blocks
called amino acids these amino acids are
the same building blocks
wherever you look in nature however they
create an astonishing
array of diversity and properties out of
universality comes diversity
that’s the hallmark of nature can we
mimic these processes and construct
superior materials from universal or
simple building blocks
this might help us solve the
sustainability crisis we’re facing today
in fact nature uses this hierarchical
patterning approach to construct
materials nano to macro
and we can create multi-functionality
even by reassembling nature’s building
blocks
along the way as we need them that way
we can make materials that aren’t static
anymore these materials can be adjusted
modified
as the need changes we call this the
universality diversity paradigm which is
one of the most
foundational aspects of how materials
are used in nature
and could provide an important clue an
important solution to the climate crisis
we’re facing
think about a tree growing from a seed
forming the first leaves
these leaves grow provide photosynthesis
great biomass
the leaves fall off in the fall they rot
and they create new soil
and the cycle repeats these kind of
biological mechanisms where
creation of structures is repeated and
recycled
is foundational in nature we look at
biomass
like old leaves or wood or many other
kinds of tailings that we find in nature
they have a very rich set of chemical
foundations within them
these chemical building blocks of
molecules can be utilized if we manage
to reassemble them to create almost any
material function we might need
that’s what nature does when you think
about a spider a spider will eat a fly
and break down the amino acids the
proteins in the fly’s body
to reassemble them to make silk which
one of the which is one of the strongest
materials known
it’s an amazing polymer silk is not made
from petroleum
silk is made from a renewable resource
silk is made from biomass from waste
we cannot yet do that we cannot yet
mimic these processes fully in the
laboratory but provides an
amazing opportunity for future engineers
for scientists to create this future
economy in which we can recycle or
reassess
material combinations from the nano to
the macro level
the paradigm that nature uses is out of
simplicity
emerges complexity and structure and
superiority function and form
we use a multi-skill modeling approach
to address this issue and to solve this
pressing engineering challenge we
simulate materials out and by atom
through the scales from molecular
dynamics to coarse grain simulations all
the way to the continuum level where we
simulate materials
as a macroscopic object that has no
internal structure
by integrating multiple simulation
paradigms we can provide powerful
solutions to how materials work and
function
and we can design them for instance
think about a spider web we can look
inside the spider web
and see that the spider web has internal
structures there are atoms inside
molecules proteins inside and these
proteins are assembled in certain
architectures
if we understand how these proteins are
assembled we can mimic this we can make
our own protein materials
we don’t necessarily have to make a
spider web we can make materials that we
need for
for engineering for instance filtration
devices batteries
structural materials for construction
and the list goes on
this bottom bottom-up approach is very
powerful and can provide a direct
connection between the genetic sequence
in a material
all the way to the functional level we
can either engineer the dna
to design how proteins fold or we can
make materials in the laboratory
synthetically and assemble them atom by
atom
thereby we can take advantage of
foundational processes like size effects
and materials where
the small scale the small length scales
that can be controlled by these
nanotechnological approaches
can provide superior function in other
words materials can become resilient
if we make the nanostructures small
enough so they can prevent
from fracturing and being fragile that’s
one paradigm in which nature uses
defects
to the contrary defects are used to
create strength
out of weakness comes strength and the
key to this is architecture all the way
down to the nano scale by creating
confinement effects where geometry
plays a key role the hierarchical design
paradigm is a very powerful way
used by nature to generate function out
of weak building blocks
for example you can look at bone bone is
made from two components protein like
jello which is very wobbly
and chalk or minerals which are very
fragile and brittle
by combining jello and chalk into a
material
across hierarchical structuring bone is
created and bone is one of the toughest
materials we know
similar materials are seashells like
conch shells which have very very high
toughness values
we’re using this approach to design with
nature instead of against nature
provide solutions that are sustainable
and work with nature
we’ve utilized this approach in a
variety of ways for instance we’ve
utilized
silk made by silkworms and created
cocoons and then re-engineered the
materials in this cocoons to 3d print it
into
various kind of textiles into very
strong materials into tunable materials
or even medical devices or even engines
or motors we can use for tunability and
functional materials i’ve also made
filtration devices out of silk
a simple process where we reassemble and
microstructures the nanostructures that
nature is creating in the in the
formation of silk fibrils
we can create manual porosity mimicking
the structure of silk cocoons
but scaling them down all the way down
to the nano levels so we can filter
out molecules this might be another
powerful way to address pollution
silicon inspired materials and devices
are very interesting because silk is a
biomaterial
that’s compatible with the human body
and other environmental systems
it’s not a synthetic polymer it’s
something that nature creates you can
eat it
and you can work with it and it’s
inexpensive so creating filtration
devices out of silk
or advanced electronics is a powerful
way of working with nature instead of
against nature
the filtration devices are very
effective and can filter out very small
molecules such as heavy metals
metal particles and other kind of
organic substances
a second approach we’ve been exploring
in my laboratory is to use waste
and rearrange the molecules inside the
waste to create
future patterns of molecules that
resemble those
found in nature in other materials to
create superior function
thereby we can mimic what the spider
does the spider will eat flies
have offspring create new silk and these
silks are powerful and very effective
in creating advanced function we can
mimic this by using a process called
hydrothermal processing or hdp in which
we use
pressure and temperature to create new
materials
by using high temperature and high
pressure we can use water as a solvent
instead of relying on petrochemical
other aggressive chemical substances
which are toxic using water in a
supercritical state
allows us to create a reactor condition
in which we can transform
biomass or waste into three main
components a
solid which is a carbon-rich material a
biofuel which provides a foundation of
creating alternative petrochemical
sources
as well as a liquid phase which can be
utilized as an adhesive
we’ve also mixed these biomass sources
that we’ve extracted from hydrothermal
processing
with silk thereby we can mimic what
nature does
combining an existing material like silk
which is amazing
which has amazing properties with the
kinds of materials that nature has
created
you through waste using this
hydrothermal process by combining the
processes created using hydrothermal
processing
with other biological materials like
silk we can create composite materials
and take advantage of the best
properties of both components
and engineer new properties into this we
can develop for instance conductive and
flexible biomaterials
that can reach strength and
cytocombability by using silk
we can also reach environmental friendly
less expensive processing conditions and
packaging conditions for food for
instance
to enhance materials further by using
grapheno carbon nanotubes
we can overcome the suitability issue of
conventional grapheno carbon nanotube
materials
by using kite in the wood or activated
carbon in a recent research study we’ve
used
shrimp waste to create chitin-rich
materials that we’ve then
processed in the hydrothermal processing
plant to create
materials that we’ve used to make
electrodes for flow batteries
this could provide a solution to both
the waste problem
as well as providing new battery
technologies that can be very powerful
in storing alternative sources like
solar or wind
we’ve also used waste from chemical
treatment plants or sewage treatment
plants
for example from the deer island
facility near boston and
use sewage sludge to process it using
hydrothermal processing to create
a biocode mimicking oil as biobinders as
an adhesive for use in adhesive
construction industry for instance
in all this work we’re paying close
attention to the techno-economic
analysis in other words
how economically feasible these
processes are and it turns out they are
feasible
if we can scale it up we’re actually
able to utilize waste
by using this nanotechnology
nanoengineering approach to transform
the ingredients to transform the waste
into functional and usable materials we
can also use these products to create
new types of adhesives
for wood-based products for example
particle wood
or plywood where we need a glue or
adhesive to con construct
materials that have strong binding
between wood particles and the
surrounding faces
using biomass provides a way of
utilizing waste
either from sewage plants or perhaps
waste from wood facilities
for example sawdust to combine these
together with existing wood technologies
to create new types of paneling that are
formaldehyde-free
and work on a low energy sustainable
economic cycle
another exciting direction of this work
is to utilize these biomass-based
waste streams and transformations in the
creation of 3d printing materials or
inks
once we have transformed a biomass or
waste into an ink material we can
construct
any geometry any architecture we can
begin to assemble materials atom by atom
from the nano to the micro to the miser
to the macro level all from these waste
materials
the function of materials derives from
the hierarchical patterns across
different scales
nature has taught us how effective this
paradigm is the concept is now
can we learn from computational methods
how to actually construct these
materials
you can imagine if you’re thinking about
hierarchical patterning the design space
is gigantic it’s very big
and it’s very difficult to find
solutions for where to put materials
what to print or what kind of materials
to actually make in the first place
that’s why we use machine learning and
artificial intelligence to solve this
problem
in machine learning we have methods that
can very accurately capture
hierarchical patterns think about image
recognition or face recognition
these algorithms for example implemented
in convolutional neural networks
use deep layers within the neural
network to detect features across
length scales and time scales these
features are used to decide whether an
image or photo
is a car tree or cat or dog in our case
we’re using these convolutional neural
networks to determine
what function the material has by
looking at its microstructure across
length scales from the protein length
scale which is basically the code of dna
the chemical composition the micro scale
the mesoscale all the way to the macro
scale shape and form of the material
deep learning is a powerful way of
capturing structured process function
relationships that are otherwise very
difficult to understand
the many other machine learning methods
that can be used in addition to
convolutional neural networks
such as deep learning based methods
based on game theory or
gans generative adversarial neural
networks which basically implement a
game theoretic approach where multiple
neural networks
multiple ais play games with each other
to find solutions to physics problems
these solutions can not only be
the solution to a physics problem like
the equilibrium forces but they can also
be
the solution to a design problem where
the algorithm will determine the optimal
design given a set of constraints
this is extremely exciting because it
enhances human creativity
in fact we can complement or supplement
human creativity by creating
augmented reality or virtual reality
environments where we can interact with
the ai system
with our senses and we can make things
seem that we cannot yet see
like forces in a material by going into
an augmented reality environment
we can see forces for instance we can
see magnetic fields
we can see things that our own senses
our own eyes cannot yet recognize
but the ei algorithm can make it visible
to our senses
and we can then use this in the design
process in other words we can see
the immediate impact of how changing the
process the nano structure
the meso scale structure the shape of a
material affects certain properties
properties we can usually not see which
are however very important for
engineering applications
like the forces in the material are
critical to prevent materials from
breaking
now we can see them using ai and
algorithmics algorithmic development is
like virtual reality
that way we can push the frontier to the
next level in which we understand how
hierarchical structures can result in
defect halloween behavior
for instance we can make materials from
waste that are superior
that are superior in strength and
resilience in other words they’re very
hard to break
think about glass glass breaks very
easily however
we don’t want to build with glass
because we don’t want to build a
structure a house a car a train an
airplane out of blast it’s very fragile
using nature’s design paradigm we can
transform brittle elements like minerals
or glass particles
into structures that are very tough as a
whole by creating these architectural
features
from the nano to the macro scale and ai
methods can teach us
how to assemble these patterns these
building blocks
this is very similar to the kinds of
problems people have already solved
using ai methods like how to play chess
or go
which can be very effective and have
proven to be a very powerful way of
solving
complex game theoretic approaches now
we’re using ai machine learning to solve
similar problems
but instead of solving how to play go we
can solve the problem the puzzling
problem
of how to design the best possible
material out of waste
that is an exciting future that allows
us to mimic nature
and yet train the problem develop a
problem solution that mimics it
such that we provide solutions for our
own problems for own challenges that
we’re facing today
such as creating high volume tough
resilient materials
green materials carbon sinks or to
create electrodes for batteries or
filtration devices or
robots or materials that have actuation
properties that are smart that can
interact with the environment
these are all challenging problems of
materials design that need
a revolutionary approach such as ai and
machine learning
now to make these materials we can use
3d printing we talked earlier about 3d
printing as a powerful way
of assembling materials atom by atom
micro by micro
all the way to the macro level in fact
we’re using these multi-scale
additive manufacturing techniques to
then assemble these waste stream derived
inks
into materials that can then be created
and applied in various industrial
settings
we can make materials with tailored
properties we can dial in we can decide
exactly
what kind of strength the material
should have kind of elasticity
when it should break what kind of
tunability properties it should have
or how it would interact with the human
body in cells or animals or other types
of environmental systems
and all of these materials can be made
with nature they can be made out of
polymers or chemicals
that are actually found in nature so
think back about the material like silk
silk is found in nature proteins are
found in nature all of us are living
examples of how nature uses proteins to
build life
now we can create new material solutions
new technologies new electronics the
future of computing perhaps
future computing architectures out of
these silk based
or protein based or amino acid based
materials which are exciting solutions
genetic algorithms allow us to provide a
simulation of evolutionary processes
by combining it with ai and machine
learning which provides
very quick very rapid computational
solutions to complex physics problems to
understand how
design changes affect changes in the
fitness or performance
by combining these ai methods with
genetic algorithms we can essentially
simulate evolution
and within a couple of hours or days in
a computer simulation design
optimal proteins these are all solutions
that can be made today
and that we’re working very hard at mit
in my lab
to create future possibilities for
future generations
to thinking the work with nature instead
of against nature and providing
a platform to use waste as a way to
create the future of materials
the experimental testing that can be
carried out based on the materials we
have created
can be fed back right into the ai model
and therefore create a reinforcement
learning approach where
the performance measured in the
laboratory can
improve the model itself and thereby
improve the design experience overall
now the human input the
human creative input the input of the
engineer comes in
through these augmented reality virtual
reality setups where
we can interact with the computational
models in different ways
we can see things we cannot yet see like
internal forces electricity
magnetic forces or other things and we
can augment the picture the
images that we can see with our eyes
through these ai methods very
effectively
in the augmented reality of virtual
reality setup
through these methods we’re hoping to
mimic nature we’re trying to work
with nature instead of against nature if
we want to address the climate challenge
if you want to address the
challenges that we are facing in future
generations in terms of sustainability
creating more food more resilience more
resources for growing population in the
world
we have to look at nature and we have a
great opportunity now with
nanotechnology
emerging as one of the most exciting
trends in science and engineering
and a platform technology combined with
computational modeling like ai and
machine learning
we can put these things together and
create solutions for future generations
that mimic nature and they build on
nature and work with nature
the future of engineering lies in
thinking about how
natural materials are designed how
they’re created how they interact
the future of materials also features
living materials materials that aren’t
static today’s engineers create
materials that are made in the factory
after they’ve been designed by an
engineer and then shipped off to the
consumer or applied
in a product and they have a lifetime
and they fail and have to be repaired
now that’s a very different paradigm
than the kind of paradigm that nature
uses
uh think about our own body our bones
they grow and if you hurt your bones you
hurt your skin
our body will try to repair these and in
many cases our body is very effective in
repairing injuries or diseases
and we are trying to get to the point
where future materials future
technologies work
just like this where we can actually
mimic the paradigm instead of creating
materials
one time and then repairing them we’re
trying to mimic this paradigm where
instead of creating materials
and shipping them off to the consumer
until they fail we
built in a repair feature we built in
the ability of a material to be
living to be more like us the material
to be more like
human beings more like insects more like
the living world around us
and being able to sense damage to
respond to the environment
and to create entirely new solutions for
engineering solutions in that way
where of course the human need the human
demand for civilization is at the center
of this
and we can work with sustainable
solutions that are carbon sinks
that use waste materials that use the
immense complexity the richness of all
the chemical waste all the chemical
tailings we have today
in the construction of materials the key
to making this happen
are three one nanotechnology to use the
ability to construct materials atom by
atom molecule molecule
second computation to use computation as
a way of understanding
what to build what to design and three
to be able to measure and sense the
environment
either using augmented or virtual
reality or advanced experimental imaging
measurements where data can be generated
in large amounts
which in turn can improve the way we
model using the artificial intelligence
method for instance
to use a reinforcement learning approach
to improve models
as we go along finally this is changing
the way engineers work
the way the physical world is modeled
goes back today
pretty much to newton’s laws where we
solve equations like differential
equations
that have been written down on a piece
of paper the future
might rely on an alternative approach or
complementary approach where in addition
to solving equations like newton’s laws
schrodinger’s equation and others like
this we can also
generate data and behavior and
understand the behavior of physical
systems
directly from observations so instead of
having newton observe how an apple falls
from the tree and then deriving a model
for this
computers can do similar things
computers can observe
how physical systems or living systems
act interact behave
how they work and then from that derive
a
deep learning or neural network based
architecture
one of the biggest threats to climate
change is the use of resources
and that’s what this research really is
about the approach used by nature is
quite distinct
when nature uses the same chemical
ingredients so instead of using
limestone like for cement
or petroleum or other types of
ingredients nature uses
the same chemical building blocks amino
acids to create virtually any function
these protein-based materials have
functions as diverse as acting as a glue
as a sensor as a robot material a
robotic material that has
activation properties that can sense the
environment i can act as a signaling
material like a cable for nerve cells
for instance
it act as a very strong material like
seen in silk being one of the strongest
materials known stronger than steel
and the list goes on these materials are
exciting they’re powerful
and yet they’re made from the same
chemical building blocks so to address
the climate challenge
we believe we need to go to that mode of
operation we want to be able to be in a
position
where we can actually create almost any
function out of almost
any feature