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Understanding the electromechanical coupling of auxetic materials offers unique opportunities to enhance the sensitivity of piezoresistive sensors. Reports on the auxetic behavior of random fiber networks have been relatively scarce due to their less pronounced Poisson's expansions than other auxetic designs adapting periodically arranged structures. In this study, the auxetic response of hierarchical pulp-carbon nanotube networks is tailored through the localized tensional micro-fracture initiated by water-printing. The interfacial junctions among multiwalled carbon nanotubes (MWCNTs) and cellulose fibers are disintegrated and reorganized to induce the buckling of a wet CNT paper composite (CPC) network. The Poisson's ratio of −49.5 is achieved at the water-printed region. The resulting piezoresistive properties of CPC sensors exhibit high sensitivity (3.3 kPa −1 ) over a wide dynamic range (6–500 000 Pa). The novel auxetic behavior of water-printed CPC paves the way for high performance and inexpensive wearable devices. 

Calculated conductance through Au n –S–Bridge–S–Au n (Bridge = organic σ/π-system) constructs are compared to experimentally-determined magnetic exchange coupling parameters in a series of Tp Cum,Me ZnSQ–Bridge–NN complexes, where Tp Cum,Me = hydro-tris(3-cumenyl-1-methylpyrazolyl)borate ancillary ligand, Zn = diamagnetic zinc( ii ), SQ = semiquinone ( S = 1/2), and NN = nitronylnitroxide radical ( S = 1/2). We find that there is a nonlinear functional relationship between the biradical magnetic exchange coupling, J D→A , and the computed conductance, g mb . Although different bridge types (monomer vs. dimer) do not lie on the same J D→A vs. g mb , curve, there is a scale invariance between the monomeric and dimeric bridges which shows that the two data sets are related by a proportionate scaling of J D→A . For exchange and conductance mediated by a given bridge fragment, we find that the ratio of distance dependent decay constants for conductance ( β g ) and magnetic exchange coupling ( β J ) does not equal unity, indicating that inherent differences in the tunneling energy gaps, Δ ε , and the bridge–bridge electronic coupling, H BB , are not directly transferrable properties as they relate to exchange and conductance. The results of these observations are described in valence bond terms, with resonance structure contributions to the ground state bridge wavefunction being different for SQ–Bridge–NN and Au n –S–Bridge–S–Au n systems. 

Coherent interactions are prevalent in numerous photodriven processes, ranging from photosynthetic energy transfer to superexchange-mediated electron transfer, resulting in numerous studies aimed towards identifying and understanding these interactions. A key motivator of this interest is the non-statistical scaling laws that result from coherently traversing multiple pathways due to quantum interference. To that end, we employed ultrafast transient absorption spectroscopy to measure electron transfer in two donor-acceptor molecular systems comprising a p-(9-anthryl)-N,N-dimethylaniline chromophore/electron donor and either one or two equivalent naphthalene-1,8:4,5-bis(dicarboximide) electron acceptors at both ambient and cryogenic temperatures. The two-acceptor compound shows a statistical factor of 2.1  0.2 rate enhancement at room temperature and a non-statistical factor of 2.6  0.2 rate enhancement at cryogenic temperatures, suggesting correlated interactions between the two acceptors with the donor and with the bath modes. Comparing the charge recombination rates indicates that the electron is delocalized over both acceptors at low temperature but localized on a single acceptor at room temperature. These results highlight the importance of shielding the system from bath fluctuations to preserve and ultimately exploit the coherent interactions. 

The global cost of diabetes care exceeds $1 trillion each year with more than $327 billion being spent in the United States alone. Despite some of the advances in diabetes care including continuous glucose monitoring systems and insulin pumps, the technology associated with managing diabetes has largely remained unchanged over the past several decades. With the rise of wearable electronics and novel functional materials, the field is well‐poised for the next generation of closed‐loop diabetes care. Wearable glucose sensors implanted within diverse platforms including skin or on‐tooth tattoos, skin‐mounted patches, eyeglasses, contact lenses, fabrics, mouthguards, and pacifiers have enabled noninvasive, unobtrusive, and real‐time analysis of glucose excursions in ambulatory care settings. These wearable glucose sensors can be integrated with implantable drug delivery systems, including an insulin pump, glucose responsive insulin release implant, and islets transplantation, to form self‐regulating closed‐loop systems. This review article encompasses the emerging trends and latest innovations of wearable glucose monitoring and implantable insulin delivery technologies for diabetes management with a focus on their advanced materials and construction. Perspectives on the current unmet challenges of these strategies are also discussed to motivate future technological development toward improved patient care in diabetes management.

 

The correlation of electron transfer with molecular conductance ( g : electron transport through single molecules) by Nitzan and others has contributed to a fundamental understanding of single-molecule electronic materials. When an unsymmetric, dipolar molecule spans two electrodes, the possibility exists for different conductance values at equal, but opposite electrode biases. In the device configuration, these molecules serve as rectifiers of the current and the efficiency of the device is given by the rectification ratio (RR = g forward / g reverse ). Experimental determination of the RR is challenging since the orientation of the rectifying molecule with respect to the electrodes and with respect to the electrode bias direction is difficult to establish. Thus, while two different values of g can be measured and a RR calculated, one cannot easily assign each conductance value as being aligned with or opposed to the molecular dipole, and calculations are often required to resolve the uncertainty. Herein, we describe the properties of two isomeric, triplet ground state biradical molecules that serve as constant-bias analogs of single-molecule electronic devices. Through established theoretical relationships between g and electronic coupling, H 2 , and between H 2 and magnetic exchange coupling, J ( g ∝ H 2 ∝ J ), we use the ratio of experimental J -values for our two isomers to calculate a RR for an unsymmetric bridge molecule with known geometry relative to the two radical fragments of the molecule and at a spectroscopically-defined potential bias. Our experimental results are compared with device transport calculations.