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Covalent bonding interactions determine the energy–momentum (E–k) dispersion (band structure) of solid-state materials. Here, we show that noncovalent interactions can modulate theE–kdispersion near the Fermi level of a low-dimensional nanoscale conductor. We demonstrate that low energy band gaps may be opened in metallic carbon nanotubes through polymer wrapping of the nanotube surface at fixed helical periodicity. Electronic spectral, chiro-optic, potentiometric, electronic device, and work function data corroborate that the magnitude of band gap opening depends on the nature of the polymer electronic structure. Polymer dewrapping reverses the conducting-to-semiconducting phase transition, restoring the native metallic carbon nanotube electronic structure. These results address a long-standing challenge to develop carbon nanotube electronic structures that are not realized through disruption of π conjugation, and establish a roadmap for designing and tuning specialized semiconductors that feature band gaps on the order of a few hundred meV. 

Abstract Solution‐processed graphene is a promising material for numerous high‐volume applications including structural composites, batteries, sensors, and printed electronics. However, the polydisperse nature of graphene dispersions following liquid‐phase exfoliation poses major manufacturing challenges, as incompletely exfoliated graphite flakes must be removed to achieve optimal properties and downstream performance. Incumbent separation schemes rely on centrifugation, which is highly energy‐intensive and limits scalable manufacturing. Here, cross‐flow filtration (CFF) is introduced as a centrifuge‐free processing method that improves the throughput of graphene separation by two orders of magnitude. By tuning membrane pore sizes between microfiltration and ultrafiltration length scales, CFF can also be used for efficient recovery of solvents and stabilizing polymers. In this manner, life cycle assessment and techno‐economic analysis reveal that CFF reduces greenhouse gas emissions, fossil energy usage, water consumption, and specific production costs of graphene manufacturing by 57%, 56%, 63%, and 72%, respectively. To confirm that CFF produces electronic‐grade graphene, CFF‐processed graphene nanosheets are formulated into printable inks, leading to state‐of‐the‐art thin‐film conductivities exceeding 10⁴S m⁻¹. This CFF methodology can likely be generalized to other van der Waals layered solids, thus enabling sustainable manufacturing of the diverse set of applications currently being pursued for 2D materials. 

This study examines language ideologies and communicative practices in the multilingual Vaupés region of northwestern Amazonia. Following a comparative overview of the Vaupés as a ‘small-scale’ language ecology, it discusses claims from existing ethnographic work on the region in light of data from a corpus of video-recordings of sociolinguistic interviews and spontaneous everyday conversations. It shows how a practice-based and interdisciplinary approach combining language documentation methodology and ethnographic, structural linguistic, and interactional perspectives can contribute to understanding of macro and micro aspects of multilingualism, thus contributing to future work on the Vaupés, typologies of small-scale multilingual ecologies, and language contact research. 

This article analyzes the use of several response particles in face-to-face interaction in Wa’ikhana, an East Tukano language of northwestern Amazonia. Adopting a Conversation Analysis approach, we explore details of each particle, considering their prosodic shapes, the action contexts in which they occur, and their sequential positioning, all crucial to understanding their meanings in interaction. Our analysis shows that Wa’ikhana response particles exhibit both universal and language-particular properties, thus demonstrating the contributions of data from lesser-studied languages to research on language in social interaction, and the value of an interactional approach in the study of under-described, and often endangered, indigenous languages. 

In the wake of widespread and ongoing travel restrictions that began in early 2020 due to the COVID-19 pandemic, many documentary linguists worldwide shifted to remote work methods in order to continue or, in some cases, begin new projects. This pandemic situation has prompted questions about both methodological and ethical considerations in doing remote fieldwork. In this paper, we discuss the pros and cons of working remotely and discuss ways of working remotely based on our experiences working on projects in West Africa, northwest Amazonia, and Indonesia. We argue that elements of remote fieldwork should become a permanent part of linguistic fieldwork, but that such methods need to be considered in the context of decolonizing language documentation and centering the community’s needs and interests.