Polymer thin films containing high-density arrays of nanotubes as through channels are very desirable as environmentally friendly and efficient selective transport systems. However, successful design and synthesis of polymer membranes that can be processed in solution and have precise subnanometer diameter pores, vertical channel alignment, and tunable pore interior chemistry similar to biological transmembrane proteins has remained challenging to produce. This project employs a collaborative theoretical / experimental effort to model, design and synthesize functionalized cyclic peptide nanotubes (CPNs) to understand mechanisms governing their assembly in solution and co-assembly with block copolymers. The objective of this research project is to generate mechanically robust self-assembling peptide nanotubes with functional interiors that could be used in selective porous membranes. To achieve this overarching objective, we will (i) fabricate and characterize porous cyclic peptide nanotubes (CPNs) functionalized with a polar (amine) group, (ii) produce layered membranes with control over the vertical distribution of CPs with polar and non-polar groups using crosslinkable block copolymer matrix, and (iii) investigate selectivity mechanisms in membranes with tunable pore functionalities toward novel transport capabilities. Validated large-scale simulation efforts will be integrated with experiments to rapidly evaluate material design parameters and predict material properties, circumventing challenges associated with purely combinatorial approaches.
This research project aims to break new ground by mapping out the nascent material space of organic nanotubes through simulations. Fresh knowledge pertaining to the underlying physics of peptide/polymer hybrid nanostructures will be foundational for generating novel functional subnanoporous membranes toward new platforms to study molecular mechanisms underpinning key transport phenomena observed in biology. K-12 outreach and undergraduate research programs at Northwestern University and the University of California, Berkeley, respectively, will be leveraged to recruit underrepresented minority students and women into the research team through summer opportunities at both institutions. An image library for organic nanotube materials will be created and will serve as an open-access database for public outreach, and for other researchers to identify broader applications of our functional nanostructures and methods. Modules for virtual and laboratory experiments will be created to promote effective learning in materials physics and chemistry at all levels, and will be contributed to NanoHub and forthcoming cyber infrastructures. Guidance and mentorship on career development as well as work-life balance will be provided for graduate students and postdoctoral fellows through interactions with academia, industry and national labs.
