For textiles containing nanosilver, we assessed benefit (antimicrobial efficacy) in parallel with potential to release nanosilver (impact) during multiple life cycle stages. The silver loading and method of silver attachment to the textile highly influenced the silver release during washing. Multiple sequential simulated household washing experiments for fabric swatches in deionized water with or without detergent showed a range of silver release. The toxicity of washing experiment supernatants to zebrafish (Danio rerio) embryos was negligible, with the exception of the very highest Ag releases (∼1 mg/L Ag). In fact, toxicity tests indicated that residual detergent exhibited greater adverse response than the released silver. Although washing the fabrics did release silver, it did not affect their antimicrobial efficacy, as demonstrated by >99.9% inhibition of E. coli growth on the textiles, even for textiles that retained as little as 2 μg/g Ag after washing. This suggests that very little nanosilver is required to control bacterial growth in textiles. Visible light irradiation of the fabrics reduced the extent of Ag release for textiles during subsequent washings. End-of-life experiments using simulated landfill conditions showed that silver remaining on the textile is likely to continue leaching from textiles after disposal in a landfill.

Bicontinuous porous structures through colloidal assembly realized by non-equilibrium process is crucial to various applications, including water treatment, catalysis and energy storage. However, as non-equilibrium structures are process-dependent, it is very challenging to simultaneously achieve reversibility, reproducibility, scalability, and tunability over material structures and properties. Here, a novel solvent segregation driven gel (SeedGel) is proposed and demonstrated to arrest bicontinuous structures with excellent thermal structural reversibility and reproducibility, tunable domain size, adjustable gel transition temperature, and amazing optical properties. It is achieved by trapping nanoparticles into one of the solvent domains upon the phase separation of the binary solvent. Due to the universality of the solvent driven particle phase separation, SeedGel is thus potentially a generic method for a wide range of colloidal systems.

8Although catalytic metal nanoparticle (NP) impurities in carbon nanotube (CNT) structures are undesirable 9 in a manufacturing context, they can be used as proxies to detect CNTs by single particle inductively 10 coupled plasmamass spectrometry (spICP-MS). The use of 100 microsecond dwell times, a recent 11 advancement for spICP-MS, increases resolution between pulse events and reduces background signal, 12 improving the detection of low metal-content CNTs. Serial filtration supports the assertion that metal NPs, 13 containing yttrium in this study, are primarily incorporated in CNT structures and remain bound to the tubes 14 throughout analysis. Analysis of both acid-digested and suspended CNTs confirmed that CNTs are fully 15 ablated in the plasma and that all residual metals are ionized. This result, combined with good agreement 16 with UV-Vis spectroscopy analysis, indicates that spICP-MS can provide quantitative CNT mass analysis.17 Though Nanoparticle Tracking Analysis (NTA) was less accurate than spICP-MS when counting Au-PVP 18 NPs, it gave higher particle number concentrations than spICP-MS for CNTs. The likely undercounting of 19 CNTs by sp-ICPMS is ascribed to the heterogeneous distribution of yttrium NPs among CNTs, and the small 20 diameter of many yttrium NPs (~15 nm), nearing their detection limit. Despite this limitation, its sensitivity 21 and elemental specificity make spICP-MS a powerful nanometrology method for environmental exposure 22 assessment of CNTs. To illustrate this capability, CNT association with Daphnia magna was measured at 23 μg/L CNT concentrations. After 48 hours of exposure to a CNT suspension, 3.48 ± 0.32% of CNTs were 24 taken up by D. magna adults. This simple and direct application of spICP-MS to detect CNTs in organisms 25 can be applied to toxicological investigations to help understand potential bioaccumulation of CNTs in 26 aquatic ecosystems. 27 28

Single particle ICP-MS is used to characterize the evolving magnitude, rate, and form of CNT release from photodegrading polymer nanocomposites.

The past decade has seen increased research interest in studying bicontinuous structures formed via colloidal self-assembly due to their many useful applications. A new type of colloidal gel, solvent segregation-driven gel (SeedGel), has been recently demonstrated as an effective approach to arrest bicontinuous structures with unique and intriguing properties, such as thermoreversibility, structural reproducibility, and sensitive temperature response. Here, using a model system with silica particles in the 2,6-lutidine/water binary solvent, we investigate the factors controlling the domain size of a SeedGel system by varying the particle concentration, solvent ratio, and quenching protocol. A phase diagram is identified to produce SeedGels for this model system. Our results indicate that by adjusting the sample composition, it is possible to realize bicontinuous domains with well-controlled repeating distances (periodicities). In addition, the effect of quenching rate on the domain size is systematically investigated, showing that it is a very sensitive parameter to control domain sizes. By further heating SeedGel up into the spinodal region, the structure evolution under high temperatures is also investigated and discussed. These results provide important insights into how to control bicontinuous structures in SeedGel systems.