Block Polymers Prove to be Promising for Nanostructured Systems

Significant advances are being introduced by high-performance materials in a wide range of applications starting from digital information storage and energy generation to medical devices and disease screening.

Block polymers show immense promise for several of these applications. These polymers are two or more polymer chains with varied properties combined together. Over the past several years, a search group at the University of Delaware has made important strides in the development of block polymers.

We are using synthesis, processing and characterization methods that are robust and widely applicable, with an eye toward scaling these methods to facilitate the future industrial adoption of block polymers.

Thomas H. Epps, III, Professor of Materials Science and Engineering University of Delaware

Epps, the Thomas and Kipp Gutshall Professor of Chemical and Biomolecular Engineering and professor of Materials Science and Engineering at UD, and two of his graduate students, Melody Morris and Thomas Gartner, recently published an article pointing out the importance of this work in Macromolecular Chemistry and Physics. The piece was a "Talent" submission, a unique kind of article dedicated to young scientists.

The Epps group's work highlighted by this article focuses on tuning and characterizing block polymers in bulk and thin film geometries. The group has leveraged expertise in materials science, chemical engineering, polymer physics and polymer chemistry to manipulate the thermal transitions, phase behavior and transport and mechanical properties of block polymers in order to optimize materials design.

"Our goal was to show how a truly multidisciplinary approach can help solve problems in the development of next-generation materials -- a development that requires simultaneous consideration of structure, properties and processing," Epps says.

He highlights battery technologies as an example.

Battery membranes and the associated electrolytes, used to help in ion transport for energy storage and generation applications can provide high performance related to minimal self-discharge, prolonged lifespan and rapid charging. However, these benefits are mostly accompanied by safety - for instance, fire and explosion - and environmental concerns.

We want to design these membranes so that we can achieve the same, or better, performance as current technologies while also reducing the potential for explosions and other catastrophic failures. At the same time, we'd like to develop the ability to process these materials at lower temperatures and with decreased amounts of harmful solvents. In other words, we want to reduce defects and mitigate threats to the environment through control of fabrication.

Thomas H. Epps, III, Professor of Materials Science and Engineering University of Delaware

The group uses nanoscale structures to enhance both device processing and performance. To perform this, high-throughput and combinatorial computational methods have been developed as these methods allow visualization of nanoscale structures with comparatively low-cost optical techniques.

"Basically, this approach enables us to minimize the number of samples that need to be measured with expensive techniques such as atomic force microscopy and transmission electron microscopy," Epps says.

Universal design rules have also been developed by the group in order to comprehend the significant factors that connect surface characteristics to nanostructure formation. These rules are applicable to a wide range of polymers and surfaces.

"These rules enable us to predict which polymers will work well with which surfaces, so, for example, we can create self-cleaning coatings that can resist fingerprint smudges on touchscreens," Epps says.

Epps is also concentrating on nanoscale patterning by employing block polymers as a low-cost alternative to lithographic methods used to produce electronic devices.

With all of this work, I think the things that set us apart are the universal approaches, the inclusion of joint experiment and theory efforts, and our unique focus on combined chemistry, physics, and processing knowledge to accelerate materials design.

Thomas H. Epps, III, Professor of Materials Science and Engineering University of Delaware