Monitoring of human bodily motion requires wearable sensors that can detect position, velocity and acceleration. They should be cheap, lightweight, mechanically compliant and display reasonable sensitivity at high strains and strain rates. No reported material has simultaneously demonstrated all the above requirements. Here we describe a simple method to infuse liquid-exfoliated graphene into natural rubber to create conducting composites. These materials are excellent strain sensors displaying 10(4)-fold increases in resistance and working at strains exceeding 800%. The sensitivity is reasonably high, with gauge factors of up to 35 observed. More importantly, these sensors can effectively track dynamic strain, working well at vibration frequencies of at least 160 Hz. At 60 Hz, we could monitor strains of at least 6% at strain rates exceeding 6000%/s. We have used these composites as bodily motion sensors, effectively monitoring joint and muscle motion as well and breathing and pulse.

Regeneration of the annulus fibrosus (AF), one of the three components of the intervertebral disc (IVD), is challenging because of the tissue complexity and our limited knowledge about AF cell biology. The purpose of this study was to determine if modulating surface chemistry of polycarbonate polyurethane (PU) scaffolds would influence annulus fibrosus cell adhesion and early tissue formation. To vary surface energy, a novel anionic dihydroxyl oligomer (ADO) was synthesized and incorporated into the PU base polymer at three different concentrations [0.05, 0.5, and 5% (wt %)]. The polymeric materials were fabricated into nanoscale fibrous scaffolds using electrospinning. PU nanofibrous scaffolds in the absence or presence of different amounts of ADO were similar in appearance. Surface energy was significantly enhanced with increasing ADO content, as indicated by the decreasing water contact angle measurements. Increasing the material surface's polar character for the scaffolds resulted in a positive enhancement of AF cell attachment. The mechanism of this effect was complex as at higher ADO concentrations, increased cell adhesion was mediated by both serum and newly synthesized proteins, whereas at low ADO concentrations the latter had minimal effect. Collagen but not proteoglycan accumulation was also modulated by increasing ADO content. This study demonstrated that nanoscale fibrous PU scaffolds containing ADO may be appropriate candidates in the formation of tissue engineered annulus fibrosus tissue, and that material surface polar character can be used to influence AF cell attachment and collagen accumulation.

The efficient penetration of drug nanocarriers into tumors is an important prerequisite for therapeutic and diagnostic success.

The presence of low-molar-mass surfactants in latex films results in detrimental effects on their water permeability, gloss, and adhesion. For applications such as coatings, there is a need to develop formulations that do not contain surfactants and have better water barrier properties. Having previously reported the synthesis of surfactant-free latex particles in water using low amounts (<2 wt %) of chains synthesized by controlled radical polymerization (Lesage de la Haye et al. Macromolecules 2017, 50, 9315-9328), here we study the water barrier properties of films made from these particles and their application in anticorrosion coatings. When films cast from aqueous dispersions of acrylate copolymer particles stabilized with poly(sodium 4-styrenesulfonate) (PSSNa) were immersed in water for 3 days, they sorbed only 4 wt % water. This uptake is only slightly higher than the value predicted for the pure copolymer, indicating that the negative effects of any particle boundaries and hydrophilic-stabilizing molecules are minimal. This sorption of liquid water is 5 times lower than what is found in films cast from particles stabilized with the same proportion of poly(methacrylic acid) (PMAA), which is more hydrophilic than PSSNa. In water vapor with 90% relative humidity, the PSSNa-based film had an equilibrium sorption of only 4 wt %. A small increase in the PMAA content has a strong and negative impact on the barrier properties. Nuclear magnetic resonance relaxometry on polymer films after immersion in water shows that water clusters have the smallest size in the films containing PSSNa. Furthermore, these films retain their optical clarity during immersion in liquid water for up to 90 min, whereas all other compositions quickly develop opacity ("water whitening") as a result of light scattering from sorbed water. This implies a remarkably complete coalescence and a very small density of defects, which yields properties matching those of some solvent-borne films. The latex stabilized with PSSNa is implemented as the binder in a paint formulation for application as an anticorrosive barrier coating on steel substrates and evaluated in accelerated weathering and corrosion tests. Our results demonstrate the potential of self-stabilized latex particles for the development of different applications, such as waterborne protective coatings and pressure-sensitive adhesives.