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EVOH’s excellent gas barrier properties have enabled its continued market growth in numerous applications including food packaging, fuel tanks, and construction. However, EVOH’s susceptibility to thermo-oxidation limits its ability to be reprocessed. While it is generally known that EVOH degradation leads to cross-linking, detailed degradation rates and mechanisms are not well established. Understanding EVOH degradation has been elusive because readily accessible thermal and spectroscopy methods do not reveal significant changes. Moreover, gel permeation chromatography requires specialized solvents and columns. We report that measuring changes in viscoelasticity with time-resolved rheology (TRR) is a facile way to monitor the temporal dynamics of EVOH degradation. TRR was performed on EVOH grades with ethylene copolymer contents of 27, 32, 48 mol%. As expected, the grade with the highest ethylene content was the most stable. However, with time, all the EVOH grades transitioned from a Carreau-like fluid to a power law fluid and no longer exhibited terminal behavior. Cole-Cole plots also revealed that EVOH relaxation evolved from rapid process into a long, complex process consistent with network formation. The mechanism of degradation was further elucidated by using 13C distortionless enhancement of polarization transfer (DEPT-135) nuclear magnetic resonance spectroscopy. These results showed that degradation occurred by ring-opening of lactone terminal groups that led to cross-linking. This enhanced understanding provides a foundation for developing methods to probe and mitigate EVOH degradation. 

Enhanced and rapid surveillance for diseases is critical to public health and meeting United Nations' Sustainable Development Goal for Good Health and Well‐being by allowing for targeted and accelerated prevention and control response strategies. Human malaria, caused byPlasmodiumspp. and transmitted by mosquitoes is no exception. Advances in sustainable materials provide an opportunity to improve fast, sustainable, and equitable testing assays. Here, naturally abundant polymers and biomaterials, such as cellulose nanocrystals (CNCs) and chitosan, were used to increase antibody density deposition on the assay detection line when compared to traditional free antibody deposition, and thus the sensitivity, of easily assembled rapid tests designed to detectPlasmodium vivaxinfective (sporozoite) parasites in mosquitoes, a critical indicator of malaria transmission. The immobilization of antibodies onto chitosan‐coated CNCs allowed for antigen detection with a lower number of antibodies used in each test; likewise, the immobilization allowed to directly place the CNC‐Ab without the traditionally needed blockers layer on the paper like bovine serum albumin (BSA). This bio‐based prototype of a paper‐based dipstick assay shows a promising pathway for the development of rapid disease surveillance tools using sustainable and globally available materials. 

Highlighting the role engineers have in solving community and global challenges has been shown to positively affect students' engineering identity development. Poor water quality and water scarcity have been recognized as a critical global issue by many organizations, including the United Nations. Students of all ages can relate to the importance of having drinkable water through their experiences with thirst, drought, floods, news stories, or just accidentally swallowing salt water while on holiday at a beach. This talk describes the development and implementation of a series of engineering education activities focused on water quality. These activities ranged from three-minute activities for community outreach events to week-long lessons for engineering freshmen. Younger students were able to readily recognize how using different types of filters and natural media can increase the clarity of water with particulate or color contamination. Middle and high school students were able to design and test filter set-ups and learn about the role of nanotechnology in water purification. They also developed analytical and data analysis skills through qualitative and quantitative water quality measurements. Freshman engineering students learned about the water industry, local and global water issues, and performed water quality sampling around their campuses using portable meters that log data via a cell phone app. The activities and results were then used to meet university-course outcomes related to the societal impacts of engineering, statistical analysis, plotting data, and written communication. By centering learning on a tangible and important engineering challenge, this work provides a flexible framework for learning and problem solving that can be tailored to the needs of students from different age groups and for different learning outcomes. 

Self-assembly of anisotropic nanomaterials into fluids is a key step in producing bulk, solid materials with controlled architecture and properties. In particular, the ordering of anisotropic nanomaterials in lyotropic liquid crystalline phases facilitates the production of films, fibers, and devices with anisotropic mechanical, thermal, electrical, and photonic properties. While often considered a new area of research, experimental and theoretical studies of nanoscale mesogens date back to the 1920s. Through modern computational, synthesis, and characterization tools, there are new opportunities to design liquid crystalline phases to achieve complex architectures and enable new applications in opto-electronics, multifunctional textiles, and conductive films. This review article provides a brief review of the liquid crystal phase behavior of one dimensional nanocylinders and two dimensional nanoplatelets, a discussion of investigations on the effects of size and shape dispersity on phase behavior, and outlook for exploiting size and shape dispersity in designing materials with controlled architectures.