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Photosynthesis is an efficient process by which solar energy is converted into chemical energy. Green photosynthetic bacteria such as Chloroflexus aurantiacus have supramolecular antenna complexes called chlorosomes attached to their cytoplasmic membrane that increase the cross section for light absorption even in low-light conditions. Self-assembled bacteriochlorophyll pigments in the chlorosome interior play a key role in the efficient transfer and funneling of the harvested energy. In this work it was demonstrated that chlorosomes can be rapidly and precisely size-characterized online in real time using an electrospray-assisted mobility-based technique. Chlorosomes were electrospraydeposited onto TiO 2 nanostructured films with columnar morphology to fabricate a novel biomimetic device to overcome the solvent compatibility issues associated with biological particles and synthetic dyes. The assembled unit retained the viability of the chlorosomes, and the harvesting of sunlight over a broader range of wavelengths was demonstrated. It was shown that the presence of chlorosomes in the biomimetic device had a 30-fold increase in photocurrent.

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We present a pneumatic approach for massive production of poly(vinyl alcohol) (PVA) filaments based on a mixing mechanism at the micrometer scale using so-called Flow Blurring (FB) atomizers. This micro-mixing is triggered by a turbulent, bubbly motion generated by implosion of a gas current into a liquid feeding tube. The energy of the gas, the liquid viscosity, and the geometry of the atomizer play an active role in the size and shape of the ejecta. The shear viscosity of aqueous solutions of PVA of various molecular weights was investigated to assess their rheological nature using a dimensionless parameter based on the solutions’ concentration and the polymer’s molecular weight and its entanglement molecular weight. The solutions exhibited a shear thinning behavior at low shear rates and a Newtonian behavior at moderate rates. PVA solution with viscosity above the threshold value is prone to forming filaments during atomization with FB devices. Analyses of the dynamics of the atomization revealed two main types of ejections depending on the liquid flow rate and viscosity: either a bundle of filaments formed from within the atomizer or a more continuous single structure developed in the vicinity of the atomizer exit. Furthermore, based on Kolmogorov’s energy cascade, we propose a scaling law for the mean filament diameter as a function of liquid properties, atomizer geometry, and imposed pressure. The present work may have significant implications in the large-scale processing of liquids leading to useful materials.

Flow blurring (FB) atomizers are relatively simple yet robust devices used for the generation of sprays from solutions of a wide range of viscosities. In this work, we have demonstrated that FB devices may also be applied for massive production of liquid filaments from polymeric solutions. They can later be transformed into solid filaments and fibers, leading to the production of so-called fiber mats. The liquid precursors consisted of poly(ethylene oxide) (PEO) solutions of varying molecular weights (10 5 [100k] to 4 × 10 6 g/mol [4M]) and concentrations. The FB device was operated in the gas pressure range of 3–6 bar. Except for solutions of PEO 100k, all solutions exhibited a shear thinning behavior. For massive filament production, a threshold polymer concentration ( c t ) was identified for each molecular weight. Below such concentration, the atomization resulted in droplets (the classical FB functioning mode). Such a threshold value decreased as the PEO molecular weight increased, and it coincides with the polymer coil overlap concentration, c *. The viscoelastic nature of the solutions was also observed to increase with the molecular weight. A 3.2 dependency of the zero-shear rate viscosity on a so-called Bueche parameter was found for filament production, whereas a nearly linear dependency was found for droplet production. In general, the mean diameter of the filaments decreased as they traveled downstream from the atomization point. Furthermore, at a given distance from the atomizer outlet and gas pressure, the mean filament diameter slightly shifted toward larger sizes with increasing PEO molecular weight. The tendency agrees well with the calculated filaments’ Deborah number, which increases with PEO molecular weight. The approach presented herein describes a high-throughput and efficient method for the massive production of viscous filaments. These may be transformed into fibers by an on-line drying step.

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Flow Blurring Ò (FB) atomization is a highly efficient method to produce aerosols. It originates from an unexpected turbulent back flow motion in the interior of the atomizer. The onset for the appearance of such pattern is dictated by a geometrical parameter, ', that is, the ratio of the distance from the tip of the liquid feeding tube to the discharge orifice (H), and the diameter of the discharge orifice (D). In this work, a FB atomizer with a nominal ' D 1/6 was used to produce water and ethanol droplets into pressurized environments (>1 MPa). The droplet size distributions and mean droplet speeds were investigated using (1) direct visualization with an ultra-high-speed video camera coupled with an automated droplet measurement (ADM) program and (2) using a light scattering instrument. Light scattering measurements, with water and ethanol, varying the driving pressure to produce the aerosol (DP), indicate a power dependence of »2/5 of the dimensionless mean droplet diameter (D/D o) on the dimensionless liquid flow rate (Q/Q o). At higher liquid flow rate, the optical resolution of the droplets is improved compared to lower volumetric flow rates, thus facilitating analyses with the ADM program. The approach outlined herein provides a guideline for characterization and implementation of the FB technology in high-pressure applications.