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diameters, compositions and orientations. In addition, the flexibility of electrospinning allows for controlling the structure (e.g. hollow fibers) and arrangement (e.g. well-ordered fiber arrays) of the fibers so that nanofibers of desired properties can be fabricated depending on the intended applications.The diameters of electrospun fibers can be easily varied from tens of nanometers to microns, and thus the fibers possess extremely high surface-to-volume ratio, making them suitable for activities requiring a high degree of physical contact, such as providing sites for chemical reactions. Membranes consisted of electrospun fibers possess relatively uniform pore size distribution and significantly high porosity and thus are good filter to capture small-sized particulates by physical entrapment [22,23,[27][28][29]. In addition, the nanofibers fabricated by electrospinning possess a relatively defect-free structure at the molecular scale, showing enhanced mechanical properties. Because of these advantages, electrospun fibers have been widely used in various applications. For example, in biomedical applications, by using biocompatible materials, electrospun fibrous scaffold have been considered as suitable substrates for tissue engineering [13][14][15][16] and artificial blood vessels [18], and also used to study the differentiation of stem cell [24]. While in the field of electromechanics, various sensors, such as tactile sensors [8,9], chemical sensors [3,5,6,10,11,17,19] and optical sensors [12], are using electrospun fibers as substrates or sensing elements.In this review, we provide an overview of electrospinning technologies, which have been developed to prepare nanofibers of different materials, ranging from inorganic ceramics to organic polymers, and systematically summarize the techniques to adjust the system parameters and thus tailor the properties of the fibers, including the fiber diameter and its surface morphology. We also highlight the advance of electrospinning techniques in creating complex structures with desired properties, such as well-aligned fiber arrays and specifically patterned fiber structure on the collector. Construction of nanofibers with more complex internal structure, such as corehttps://doi.org/10.1515/nanofab-2018-0002Received December 21, 2017; accepted March 19, 2018 Abstract: Electrospinning can produce nanofibers with extremely high surface-to-volume ratio and well tunable properties. The technique has been widely used in different disciplines. To fabricate fibers with required properties, parameters of fabrication should be well controlled and adjusted according to specific applications. Modification of electrospinning devices to align fibers in highly ordered architectures could improve their functions. Enhanced efficiency have also been obtained through the upscaling modification of spinnerets. With the outstanding efficiency, electrospinning has exhibited huge potentials to construct various nanostructures, such as artificial vessel, membrane for desalination and so on.

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Smectics of achiral, tilted bent-core liquid crystal molecules are chiral, but their optical activity is generally small. Here, we study the effect of conformational chirality on optical activity in smectic phases of an achiral, bent-core mesogen, W513. The neat material has a modulated B4 phase, which appears dark under crossed polarizers and shows no observable optical rotation under decrossed polarizers. However, mixtures of W513 with a rod-like mesogen, 8CB, show a conventional B4 phase, in which distinct left- and right-handed chiral domains with opposite optical activity are observed. The optical behavior of the mixtures is consistent with NMR results, which show a splitting of the carbonyl peak of the bent-core molecules into two, indicating a twisted conformation between the two molecular arms of the bent-core molecules as in conventional B materials.