Making nanoparticle building blocks for new materials
Some researchers are pushed by the hunt to enhance a selected product, like a battery or a semiconductor. Others are motivated by tackling questions confronted by a given business. Rob Macfarlane, MIT’s Paul M. Cook dinner Affiliate Professor in Supplies Science and Engineering, is pushed by a extra basic need.
“I wish to make issues,” Macfarlane says. “I need to make supplies that may be purposeful and helpful, and I need to achieve this by determining the essential rules that go into making new constructions at many various measurement ranges.”
He provides, “For lots of industries or kinds of engineering, supplies synthesis is handled as a solved drawback — making a brand new system is about utilizing the supplies we have already got, in new methods. In our lab’s analysis efforts, we frequently have to coach those who the rationale we will’t do X, Y, or Z proper now could be as a result of we don’t have the supplies wanted to allow these technological advances. In lots of circumstances, we merely don’t know make them but. That is the aim of our analysis: Our lab is about enabling the supplies wanted to develop new applied sciences, quite than specializing in simply the top merchandise.”
By uncovering design rules for nanocomposites, that are supplies constructed from mixtures of polymers and nanoparticles, Macfarlane’s profession has step by step developed from designing specks of novel supplies to constructing purposeful objects you may maintain in your hand. Ultimately, he believes his analysis will result in new methods of constructing merchandise with fine-tuned and predetermined mixtures of desired electrical, mechanical, optical, and magnetic properties.
Alongside the way in which Macfarlane, who earned tenure final yr, has additionally dedicated himself to mentoring college students. He’s taught three undergraduate chemistry programs at MIT, together with his present course, 3.010 (Synthesis and Design of Supplies), which introduces sophomores to the elemental ideas needed for designing and making their very own new constructions sooner or later. He additionally just lately redesigned a course during which he teaches graduate college students be educators by studying do issues like write a syllabus, talk with and mentor college students, and design homework assignments.
Finally, Macfarlane believes mentoring the following technology of researchers is as essential as publishing papers.
“I’m lucky. I’ve been profitable, and I’ve the chance to pursue analysis I’m captivated with,” he says. “Now I view a serious part of my job as enabling my college students to achieve success. The true product and output of what I do right here is not only the science and tech developments and patents, it’s the scholars that go on to business or academia or wherever else they select, after which change the world in their very own methods.”
From nanometers to millimeters
Macfarlane was born and raised on a small farm in Palmer, Alaska, a suburban neighborhood about 45 minutes north of Anchorage. When he was in highschool, the city introduced finances cuts that may pressure the college to reduce numerous lessons. In response, Macfarlane’s mom, a former faculty instructor, inspired him to enroll within the science schooling lessons that may be provided to college students a yr older than him, so he wouldn’t miss the possibility to take them.
“She knew schooling was paramount, so she mentioned ‘We’ll get you into these final lessons earlier than they get watered down,’” Macfarlane recollects.
Macfarlane didn’t know any of the scholars in his new lessons, however he had a passionate chemistry instructor that helped him uncover a love for the topic. Consequently, when he determined to attend Willamette College in Oregon as an undergraduate, he instantly declared himself a chemistry main (which he later adjusted to biochemistry).
Macfarlane attended Yale College for his grasp’s diploma and initially started a PhD there earlier than shifting to Northwestern College, the place a PhD scholar’s seminar set Macfarlane on a path he’d comply with for the remainder of his profession.
“[The PhD student] was doing precisely what I used to be concerned with,” says Macfarlane, who requested the scholar’s PhD advisor, Professor Chad Mirkin, to be his advisor as nicely. “I used to be very lucky after I joined Mirkin’s lab, as a result of the undertaking I labored on had been initiated by a sixth-year grad scholar and a postdoc that revealed an enormous paper after which instantly left. So, there was this wide-open area no person was engaged on. It was like being given a clean canvas with a thousand various things to do.”
The work revolved round a exact approach to bind particles collectively utilizing artificial DNA strands that act like Velcro.
Researchers have identified for many years that sure supplies exhibit distinctive properties when assembled on the scale of 1 to 100 nanometers. It was additionally believed that constructing issues out of these exactly organized assemblies might give objects distinctive properties. The issue was discovering a approach to get the particles to bind in a predictable manner.
With the DNA-based method, Macfarlane had a place to begin.
“[The researchers] had mentioned, ‘Okay, we’ve proven we will make a factor, however can we make all of the issues with DNA?’” Macfarlane says. “My PhD thesis was about creating design guidelines in order that for those who use a selected set of constructing blocks, you get a identified set of nanostructures because of this. These guidelines allowed us to make a whole lot of various crystal constructions with completely different sizes, compositions, shapes, lattice constructions, and so forth.”
After finishing his PhD, Macfarlane knew he needed to enter academia, however his largest precedence had nothing to do with work.
“I needed to go someplace heat,” Macfarlane says. “I had lived in Alaska for 18 years. I did a PhD in Chicago for six years. I simply needed to go someplace heat for some time.”
Macfarlane ended up at Caltech in Pasadena, California, working within the labs of Harry Atwater and Nobel laureate Bob Grubbs. Researchers in these labs have been finding out self-assembly utilizing a brand new sort of polymer, which Macfarlane says required a “utterly completely different” skillset in comparison with his PhD work.
In 2015, after two years of studying to construct supplies utilizing polymers and absorbing the solar, Macfarlane plunged again into the chilly and joined MIT’s school. In Cambridge, Macfarlane has centered on merging the meeting strategies he’s developed for each polymers, DNA, and inorganic nanoparticles to make new supplies at bigger scales.
That work led Macfarlane and a gaggle of researchers to create a brand new sort of self-assembling constructing blocks that his lab has dubbed “nanocomposite tectons” (NCTs). NCTs use polymers and molecules that may mimic the flexibility of DNA to direct the self-organization of nanoscale objects, however with much more scalablility — that means these supplies may very well be used to construct macroscopic objects that may an individual can maintain of their hand.
“[The objects] had managed composition on the polymer and nanoparticle stage; they’d managed grain sizes and microstructural options; and so they had a managed macroscopic three-dimensional kind; and that’s by no means been performed earlier than,” Macfarlane says. “It opened up an enormous variety of potentialities by saying all these properties that individuals have been finding out for many years on these nanoparticles and their assemblies, now we will really make them into one thing purposeful and helpful.”
A world of potentialities
As Macfarlane continues working to make NCTs extra scalable, he’s enthusiastic about numerous potential purposes.
One includes programming objects to switch vitality in particular methods. Within the case of mechanical vitality, for those who hit the article with a hammer or it have been concerned in a automobile crash, the ensuing vitality might dissipate in a manner that protects what’s on the opposite facet. Within the case of photons or electrons, you would design a exact path for the vitality or ions to journey via, which might enhance the effectivity of vitality storage, computing, and transportation parts.
The reality is that such exact design of supplies has too many potential purposes to depend.
Engaged on such basic issues excites Macfarlane, and the probabilities coming from his work will solely develop as his workforce continues to make advances.
“In the long run, NCTs open up many new potentialities for supplies design, however what may be particularly industrially related is just not a lot the NCTs themselves, however what we’ve discovered alongside the way in which,” Macfarlane says. “We’ve discovered develop new syntheses and processing strategies, so one of many issues I’m most enthusiastic about is making supplies with these strategies which have compositions that have been beforehand inaccessible.”