CAREER: Harnessing the self-assembly of renewable nanomaterials by exploiting topochemical interaction with solid substrates for controlled design of advanced sustainable materials

NON-TECHNICAL SUMMARY:

Nature is a constant source of inspiration for both art and science, particularly in the fields of materials design and innovation. Over the past 30-years, scientists have discovered renewable nanomaterials—tiny particles made from common, renewable resources like wood and crops. These materials combine the benefits of advanced technology with sustainability and safety, offering potential solutions to global challenges.

Cellulose nanocrystals (CNCs), which are tiny, rod-shaped particles, are an example of renewable nanomaterials. CNCs can naturally form strong, color-producing structures, which have potential uses in products like coatings, textiles, and electronic devices. However, the exact factors that control how CNCs assemble and create colors are not yet well understood.

This research focuses on studying how different surfaces and drying conditions affect the assembly of CNCs. By uncovering these details, this project seeks to create sustainable colors and materials, leading to innovations like smart windows, anti-corrosion coatings, and even semiconductors. This project also includes a significant educational component that focuses on engaging college students, middle-school teachers and the public in science, technology and sustainability.

This project specifically fosters interdisciplinary educational opportunities, involving hands-on learning, research experience, peer-teaching and mentoring, and partnerships between academia, local schools and communities. TECHNICAL SUMMARY:

The goal of this CAREER program is to develop a scientific foundation and an interdisciplinary, inclusive education platform to harness the self-assembly of renewable nanoparticles on solid surfaces for the controlled design of advanced sustainable materials and bio-inspired colors. Of particular interest are cellulose nanocrystals (CNCs), plant-based nanoparticles that spontaneously self-assemble in aqueous suspensions to form chiral nematic structures at critical concentrations.

These helicoidal structures achieve an arrested state which may be characterized as strong, color-generating nanostructures as a result of drying the colloidal state into a coating or a film (a process referred to as EISA or evaporation-induced self-assembly). The substrates onto which the dispersions dry are hypothesized to critically influence the self-assembly of CNCs, which in turn controls the generated visible colors.

This program, therefore, aims to (1) elucidate the role of mounting substrate effects on the assembly and anchoring of these CNCs and (2) investigate the influence of drying dynamics on EISA, known to primarily govern color generation. A series of mounting substrates of varying surface properties and topography is used to investigate the deposition of CNC mono- and multilayers and assess the influence of substrate properties and external drying conditions on the drying dynamics of CNC cholesteric structures and the formation of colors.

The outcomes of aims (1) and (2) are to be integrated into a novel interdisciplinary, multi-generational educational platform that will train the next generations of leaders in bio-inspired and sustainable colors for materials design and innovation. This platform will also aim to (3) develop a globally competitive STEM workforce to increase the engagement of younger generations from all backgrounds and the broader public in science, technology and sustainability.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.