A newly designed and highly tunable macromolecule could lead the way to a new class of advanced, functional polymers with applications in nanotechnology and elsewhere, say researchers at The University of Akron (UA), Akron, Ohio. The team led by Stephen Z.D. Cheng, professor at UA’s college of polymer science and polymer engineering, in collaboration with researchers at Peking University in China and The University of Tokyo in Japan, designed and synthesized an original class of giant tetrahedra, keeping its material-specific properties, thus enabling construction of new building blocks with high precision.
Figure 1. Professor Cheng and his team have created a new molecule for constructing building blocks with high precision. Source: The University of Akron.
“Because of the ‘click’ synthesis, this system is highly tunable in terms of core structure, nanoparticle functionality, and feature sizes,” notes Cheng.
When building macromolecules, keeping their material-specific properties is a challenge that requires creating material designed and engineered at the nanometer scale for a specific task. So, Cheng and his team extended the molecular geometry of traditional one-dimension giant tetrahendra to three dimensions of tetrahedron shapes that are simple to work with to develop the new class of giant molecules that can be precisely and manually controlled and designed.
“This class of new hybrid materials could be custom designed for many functional materials including applications in nanotechnologies,” notes Joe Akkara, a materials science program director at the National Science Foundation, which funded the work, and which has provided a $700,000, 5-year grant to continue the development.
The research, highlighted in an article in a recent issue of Science, involved constructing nanosized giant tetrahedra by placing different polyhedral oligomeric silsesquioxane molecular nanoparticles at the vertices of a rigid tetrahedral framework.
Cheng says the work took three years and “had never been done before in soft matter, where it’s engineering could be particularly useful.”
“For example, we are currently exploring the intriguing functional properties of light ceramic materials with soft-matter characteristics, often called ‘soft-ceramics.’ These structures exhibit certain mechanical elasticity as opposed to the brittleness of common ceramics,” he elaborates.
In addition, the rigid single-component soft-matter systems offer potential for building supramolecular metal alloy analogs. “Metal alloys require atoms with at least two different sizes and therefore, two different components. In our case, we only use one type of molecules. The molecules will selectively assemble to form two different types of spherical building blocks,” explains Cheng.
The research is “just in the beginning,” says Cheng. “We are focusing on further developing new hybrid materials with specific desired functionalities and seeking technological applications in different fields.”
The team plans to study other types of polyhedra and see how they will assemble to obtain new structures. It will take another five years to fully explore what this class of materials can perform. Work on a larger laboratory scale will depend upon the research’s progress, he adds.
The team also aims to identify practical uses for the technology, such as in bio, information technology and other technological applications. The key challenge, notes Cheng, is that the approach requires a new thought process. “It needs to be out of [the] traditional polymer box. Starting from design, synthesize new hybrid materials and let them go through modular assembly processes to form desired structures,” he explains. New science and technology such as this requires interdisciplinary approaches, he adds.