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A major challenge in nanotechnology is that of determining how to introduce green and sustainable principles when assembling individual nanoscale elements to create working devices.For instance, textile nanofinishing is restricted by the many constraints of traditional pad-drycure processes, such as the use of costly chemical procedures to produce nanoparticles (NPs), the high liquid and energy consumption, the production of harmful liquid waste, and multi-step batch operations. By integrating low-cost, scalable, and environmentally benign aerosol processes of the type proposed here into textile nanofinishing, these constraints can be circumvented while leading to a new class of fabrics. The proposed one-step textile nanofinishing process relies on the diffusional deposition of aerosol NPs onto textile fibers. As proof of this concept, we deposit Ag NPs onto a range of textiles and assess their antimicrobial properties for two strains of bacteria (i.e., Staphylococcus Aureus and Klebsiella Pneumoniae).The measurements show that the logarithmic reduction in bacterial count reaches ca. 5.5 (corresponding to a reduction efficiency of 99.96%) when the Ag loading is one order of magnitude less (10 ppm; i.e., 10 mg Ag NPs per kg of textile) than in the textiles treated by traditional wet-routes. The antimicrobial activity does not increase in proportion to the Ag content above 10 ppm as a consequence of a "saturation" effect. Such low loading for

A recently developed Differential Mobility Analyzer (DMA) of high resolving power (50 for ions of mobility equivalent diameter∼1 nm) has been used to measure the mobility distribution of laboratory air ions generated by 241 Am and corona discharge. In the case of 241 Am, it has been possible to follow the changes in mobility during the early stages of ion aging: within the time interval between 10 and 30 ms after ion formation, the mean reduced mobility of positive ions decreased from 1.30 to 1.15 cm 2 /Vs, and that of negative ions from 2.0 to 1.75 cm 2 /Vs. The mobility distribution of air ions at the outlet of a corona ionizer strongly depends on the corona voltage, mainly due to the mobility-dependent extent of electrostatic losses within the ionizer. The mean reduced mobility of corona ions ranged between 1.01 and 1.20 cm 2 /Vs (positive) and 1.76 and 1.96 cm 2 /Vs (negative).

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The feasibility of UV photoionization for single unipolar charging of nanoparticles at flow rates up to 100 l·min −1 is demonstrated. The charging level of the aerosol particles can be varied by adjusting the intensity of the UV radiation. The suitability of a UV photocharger followed by a DMA to deliver monodisperse nanoparticles at high aerosol flow rates has been assessed experimentally in comparison to a radioactive bipolar charger ( 85 Kr, 10 mCi). Monodisperse aerosols with particle sizes in the range of 5 to 25 nm and number concentrations between 10 4 and 10 5 cm −3 have been obtained at flow rates up to 100 l·min −1 with the two aerosol chargers. In terms of output particle concentration, the UV photoionizer performs better than the radioactive ionizer with increasing aerosol flow rate. Aerosol charging in the UV photoionizer is described by means of a photoelectric charging model that relies on an empirical parameter and of a diffusion charging model based on the Fuchs theory. The UV photocharger behaved as a quasiunipolar charger for polydisperse aerosols with particles sizes less than 30 nm and number concentrations ∼10 7 cm −3 . Much reduced diffusion charging was observed in the experiments, with respect to the calculations, likely due to ion losses onto the walls caused by unsteady electric fields in the irradiation region.

Abstract.A high-resolution differential mobility analyzer (DMA), specially designed for (i) the measurement of ion mobility spectra, and (ii) the generation of a continuous stream of monomobile ions, has been developed and tested. The apparatus consists of two parallel-plate electrodes between which an electric field is applied. The test ion stream flows into the instrument through a narrow rectangular slit made in one of the electrodes, and migrates toward the other electrode driven by the applied field, while being transported by a stream of clean air which flows parallel to the plates at Reynolds number between 2×10 4 and 9×10 4 in laminar flow conditions. The collector electrode contains also a narrow slit through which ions of the desired mobility are withdrawn out of DMA. The classified ion current is measured with a highsensitivity electrometer having a noise level around 0.1 fA.The theory behind the DMA operation is first discussed, focusing on the special case of parallel-plate geometry. Some generic results showing the stability and repeatability of the measurements and the resolving power of the instrument are presented next. The last part of the paper deals with the application of the apparatus to the study of the effect of humidity and aging time on the mobility spectra of air ions generated by a low-activity 241 Am source.