Emily Grace Ripka Banner
January 15th, 2019

Why NMR?

There is something quite entrancing about NMR which I have tried to pinpoint over the past few years to no avail. It could be the elegant, calculated manor in which nuclei sway when perturbed by a magnetic field. Each atom carefully dancing in beat with their neighbors, gently settling back into the most relaxed state. Or perhaps it has something to do with how every bit of information needed to understand where your experiment went astray is delicately buried inside the data the instrument acquired in the same rhythm that the nuclei were dancing back into place. What ever it may be, I have been bitten by the NMR bug and am continually driven to unravel its seemingly infinite potential.

You may still ask, why NMR? Well, I will try to explain. You see, I have something I like to call the "passion problem". For as long as I can remember, I have been driven by passion. My first, and forever passion, was running. Again, there was something so entrancing about training not only my body but more importantly, my mind. There's nothing like the feeling of a muddy fall cross country race at the peak of the season. You're at your strongest, and it's almost like an out-of-body experience. Cruising through the woods, picking off your competitors one by one, slowly realizing their lack in training and passion in comparison to your own, and then blasting past them. Like NMR, after all these years I can't put my finger on why I was so invested in running, so I have just chocked it up to passion.

Then came my academic passions. Utterly fascinated by the mineralogical world, I devoured the coursework, and found myself day-dreaming about the world far beneath our feat. Not necessarily far in miles, but far in nanometers. The tiny little building blocks that nestle perfectly inline with their neighbors to form every inorganic structure we see; from tiny grains of sand on Hawaii's green-sand beaches, to their powerful lava flows spewing from the volcanoes. I couldn't get my mind off of how each tiny little crystals grows from this lava as it slowly cools upon reaching earth's air. How the crystals feed off of the nutrients in their surrounding lava, and that the composition of these igneous rocks can tell us about where it came from, and what environment it experienced deep within the earth.

Not being able to look at a rock, crystal, or gemstone without my mind wandering back to the beginning of its growth, I knew that this was a new passion of mine. Not only did I want to understand how and why crystals grew as such, but a part of me wanted to play God, and control their growth.

Much like people, there are four things needed to grow crystals: (1) heat, (2), pressure, (3) time, and (4) nutrients (aka ions). Perturb any of these, and you can alter the product that you get. The aspect I found most intriguing was the supply of ions to the crystal. In fact, by controlling the timing, amount, and structure (free ions vs ion complexes) of which ions are introduced to the growing crystal, you can control the size and shape of the crystal! This is one of the fundamental aspects of growing nanomaterials from solution, and thus was a natural branching point of my interests.

Again, fascinated by my newly acquired knowledge, I jumped into the field of nanomaterials. Something I soon realized was just how sensitive nanomaterials are to interactions at/with their interface both during and after growth. For example, by simply changing the length of some of the long chain organic molecules you can grow rod-shape nanoparticles instead of spheres. Importantly, these molecules are very important for keeping those tiny little growing crystals, tiny. Further, after you stop the reaction and store your little gems, the growth molecules are extremely important for keeping the gems suspended in solution, because they are stuck to their surfaces. I like to think of the molecules as the little crystals' arms which are constantly treading water to keep them from sinking. Because the crystals are bigger than ions, they will sink to the bottom of the the solution if not kept afloat with their "arms".

Gif depicting the role that molecules play in suspending nanoparticles in solution.

Depiction of the role that molecules play in suspending nanoparticles in solution.

Depending on the type of nanoparticle, and the type of "arms", these extremities can be ripped off, leading to the aforementioned crashing out of solution, and/or degradation of the particles and their properties. Now this is a problem that I just couldn't put down. I wanted to solve this, however how the heck can we see the arms of the particles, and how do we know if they are stuck to their surface, or if they are ripped off and floating in solution? How do we know how new "arms" are playing with the starting ones at the surface? How can we quantify this? How can we monitor changes in the arms attachment in different environments (i.e. temperature, pH, pressure, nutrient composition)?

This is where NMR comes in! Otherwise known as Nuclear Magnetic Resonance, NMR allows us to "see" the arms of the particles, and monitor changes to their proximity and sticking-strength over time and in various environments. So yes, I again have found a new passion.

By now, you have likely started to see a trend here -- I am a passion seeker. While I love to dig myself deeper into the pit of passion, I will forever crave the feeling of the "unknown". I truly don't ever want to reach the bottom of the pit when I am exploring these unknown worlds. I am only content when I feel like there is so much more to learn and to explore of a domain, and thus I always find myself turning down another dark passage with nothing but the glimmer in my eye from the dying torch in my hand. I thrive in worlds where I am not an expert, but a learner.

So you see, the current hole I am digging myself into is home to NMR, for now. But I can make no promises to myself or anyone else that I won't break into a new tunnel along the journey and be hypnotized by something new. I can however, make a promise that I will always be driven by my burning passions, and have them drive me in the direction I am destined to head in.

All thoughts and opinions are my own and do not reflect those of my institution.