Chemistry professor Chenfeng Ke’s lab, the Ke Functional Materials Group, recently created a 3D-printed smart material that can support up to 15 times its own weight.
At the head of the project are Ke and first-year graduate students, Qianming Lin and Hao-yi Wang. The group began research this last September into the manipulation of a gelatin-like material called hydrogel through 3D printing and immersion in solutions. This past March, they published their findings in the Angewandte Chemie International Edition.
Lin explained that the lab’s research stems from their ability to manipulate at a molecular level. Specifically, they have capitalized on the recent advent of molecular machines, nanoscale molecules made to do focused work like lifting objects. The molecular machine of interest for Ke’s group is rotaxane, a dumbbell-shaped molecule that appears similar to a cable with multiple rings along its central cable.
Wang said that during their research, they immersed hydrogel, which contains these rotaxanes, in solutions that could alter the molecular structure of the hydrogel. Outside of the solution, the rotaxanes’ rings are in a “shuttling state” along the central cable, meaning they are freely flowing along the different cables of the molecule. Once in solution, however, the rotaxanes’ rings latch together, entering a “stationary, rigid state,” Wang said.
To scale the innovation up in size, Lin explained that his group has used 3D printing to go from the molecular level to the macroscopic level — a significant upgrade. The group first printed a lattice-like 3D structure made from the hydrogel polymer about the size of a cookie from the Class of ’53 Commons. In its rigid state in solution, the polymer was able to lift a dime, the weight of which is 15 times that of the hydrogel.
“Imagine a human lifting a car,” Lin said.
Their research has been covered extensively within the scientific community. While the research currently remains small in scale and applicability, Lin and Wang said they have large aspirations. Lin specifically noted that they hope to use their smart material to innovate in preexisting technologies.
“All the robots we have are made of metal and electricity,” Lin said. “Our dream is to make a soft robot using our soft material.”
Wang then said that such advancement will take many years and will require that they do more fundamental research into controlling the molecular motions and networks to better integrate more complex 3D structures. After all, they said, going from creating a cube to designing a human-like hand is a difficult task.
Engineering student Connor Haines ’20 said he is excited by the possibilities that could result from the research Ke, Lin and Wang are conducting.
“If they can achieve their end goal, that could have huge significance,” Haines said. “There’s definitely a lot of applicability, and I think, if they are able to do what they want to do, a lot of doors will open.”
