Q&A with chemistry professor Sergei Sheiko about shapeshifting material

Sergei Sheiko, a professor in the UNC Department of Chemistry, was recognized as the senior author for a research paper on material that can be programmed to shapeshift over time.

Staff Writer Jordyn Connell spoke with him about the impact his study could have on the future of practical and biomedical materials.

The Daily Tar Heel: Is there any background information that you would like to say about the study itself?

Sergei Sheiko: We design different types of materials and most of the materials, for some implications, people would like to design similar responsive materials which change their properties in response to a certain external trigger. For example, you increase temperature and material undergoes thermal expansion. Or you increase temperature and ice can melt to water. Or there is other material that can have similar responses. In many cases people either do not want to have any stimulus, or the stimulus is not permitted. And people simply would like that this material (changes) properties, not in response to an external trigger, but as a function of time.

DTH: Why is this research significant but also relevant?

SS: Biomedical implications. Let’s assume people are interested in noninvasive or minimally invasive surgery.

DTH: What prompted you to do this research?

SS: Shape memory of materials always need and assume some kind of trigger, because basically you can program different shapes that can go from shape A to shape B, which is very nice and both shapes are programmable and defined, but in order to have this change in these shapes you always need to apply a trigger — you need to change temperature, change pH or change salinity of water. So in many cases this stimulus is not needed. What I mentioned before, for biomedical implications, like for minimally invasive surgery, you do not need this. I mean, how would you change temperature inside your body? It’s impossible. I think it would be, from a financial point of view, a very nice challenge to develop a new class of materials that are time programmable and have some kind of clock inside. 

DTH: How can the research be applied medically or to other parts of our lives?

SS: You go to Home Depot, you buy cement or concrete, you pour water on it and it becomes hard immediately. Not immediately but, more or less, it’s quickly. But let’s assume you would have a cement that you would pour water on it, but it will become hard exactly let’s say, at 2:00 p.m. on Monday.

DTH: Can you talk about what kind of impact this would have on the future?

SS: More materials will be developed with a molecularly controlled clock. Maybe somebody will pick up what we have now, some of the biomedical specialists will get in contact with our medical school, and hopefully somebody will like it and appreciate it.

DTH: Do you have anything else you would like say about yourself or the study?

SS: Usually shape memory is an irreversible process basically — increase temperature and materials stretch from shape A to shape B — so our first achievement was we made this process reversible, which was quite revolutionary.

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