Top-down fabrication of nanostructures with high throughput is still a challenge. We demonstrate the fast (>10 m/min) and continuous fabrication of multilength scale structures by roll-to-roll UV-nanoimprint lithography on a 250 mm wide web. The large-area nanopatterning is enabled by a multicomponent UV-curable resist system (JRcure) with viscous, mechanical, and surface properties that are tunable over a wide range to either allow for usage as polymer stamp material or as imprint resist. The adjustable elasticity and surface chemistry of the resist system enable multistep self-replication of structured resist layers. Decisive for defect-free UV-nanoimprinting in roll-to-roll is the minimization of the surface energies of stamp and resist, and the stepwise reduction of the stiffness from one layer to the next is essential for optimizing the reproduction fidelity especially for nanoscale features. Accordingly, we demonstrate the continuous replication of 3D nanostructures and the high-throughput fabrication of multilength scale resist structures resulting in flexible polyethylenetherephtalate film rolls with superhydrophobic properties. Moreover, a water-soluble UV-imprint resist (JRlift) is introduced that enables residue-free nanoimprinting in roll-to-roll. Thereby we could demonstrate high-throughput fabrication of metallic patterns with only 200 nm line width.

ILICATE glasses can contain relatively large amounts of S dissolved gases, principally water vapor, CO,, CO, SOn, On, and N2. These gases are dissolved in the melt; under conditions of relative supersaturation, however, they begin to form a separate gaseous phase, thus forming bubbles, one of the most undesirable defects in glass. In glasses containing relatively large amounts of B203, water vapor is the major constituent of the dissolved gases. To detect and quantitatively determine the amount of water dissolved in glasses, measurement of the infrared absorption caused by OH groups has been found most ~onvenient.'-~ The present note reports results obtained in a study of infrared water determination in a nonalkali glass.Marbles of a typical nonalkali glass used for drawing continuous fibers ( E glass) were used; their composition (in wt%) was SiOI 50.86, A1,03 14.84, BzO, 10.12, CaO 17.95, MgO 4.79, Na,O 0.98, and BaO 0.17%.Samples with varying OH-concentrations were prepared from this glass by bubbling steam through 120 g of the melt at 1200°C for 15, 30, 45, and 60 min. Since the original glass contained water, samples with lower water contents were obtained by bubbling dry Nz through the melt for 20 rnin (Table I ) . Specimens 1 mm thick were prepared from these glasses; their infrared absorptions were measured from 2000 to 4000 cm-.'. The glasses were then remelted, and dry N2 was bubbled through the melt to remove part of the water, which was absorbed and weighed in a Pregl-type apparatus. In agreement with bar lo^,^ the volatilization of B,O, under these conditions was negligible. To avoid retrapping water in the apparatus, zonal heating techniques were used. The infrared absorbance of the "dried" glasses was measured, and the difference in extinction before and after the drying was compared with the amount of water removed. The Lambert-Beer law was used to calculate the extinction coefficient of the OH band.

An innovative strategy for electrostatically designing the electronic structure of 3D bulk materials is proposed to control charge carriers at the nanoscale. This is achieved by shifting the electronic levels of chemically identical semiconducting elements through the periodic arrangement of polar functional groups. For the example of covalent organic networks, by first-principles calculations, the resulting collective electrostatic effects are shown to allow a targeted manipulation of the electronic landscape such that spatially confined pathways for electrons and holes can be realized. Mimicking donor-acceptor bulk heterojunctions, the new materials hold high promise for photovoltaic applications. The distinct advantage over the conventional approach of splitting excitons through chemically distinct donor and acceptor units is that here the magnitude of the band offset can be continuously tuned by varying the dipole density. A particularly promising feature of the suggested strategy is its structural versatility, which also enables the realization of more complex quantum structures such as quantum-cascades and quantum-checkerboards.

Chalcogenide-halide /C -H/ glasses for infrared optical fibers were studied, using compositions from the Ge -Se -I, As -Se -I and As -S -I systems, which exhibited good forming ability and thermal stability. By substituting I for Se, As -I or Ge -I bonds appeared, the concentration of As -Se or Ge -Se bonds decreased and intrinsic multiphonon absorption at 10 um was also diminished. The prepared glasses were characterized by lower T values; for fiber formation, a new method utilizing pumping glass melts into capillariesghas been developed.

Roll-to-roll UV nanoimprinting is a powerful method for the mass fabrication of nano-and microstructured surfaces, which are highly interesting for many technological applications (e.g., in the fields of optics, electronics, biomimetic, and microfluidics). When setting up a production process based on this technique, one of the main challenges is the prevention of defects (mainly entrapped air during filling and fractures during demolding). This can be cost-and time-intensive as it is mainly done by trial and error. An improved theoretical understanding of defect generation and its prediction for certain material and process parameters is therefore desirable. To accomplish this, we developed COMSOLbased two-dimensional (2D) and three-dimensional (3D) computer simulations for the two key stages of UV nanoimprinting (filling and demolding) and validated them by corresponding roll-to-roll as well as step-and-repeat experiments. Regarding filling, the investigated parameters are template and substrate contact angles; resin viscosity, velocity, and thickness during filling; as well as feature geometry. In summary, it is beneficial for filling to have low template contact angles; high substrate contact angles; low resin viscosity and velocity; as well as inclined sidewalls, low-aspect-ratio features, and a sufficient resin thickness (whereby lack of one of these factors can be compensated by others). Interestingly, nanoscale features are much easier to fill than microscale features in practice (which is not due to reduced bubble trapping but due to enhanced gas dissolution). Regarding demolding, we studied the sidewall angle, fillet radius, size, and elastic modulus of the features. In addition, we compared demolding by roll-to-roll and by stepand-repeat considering the radius of rotation and we decoupled bending, adhesion, and friction to investigate their relative contributions. We could demonstrate quantitatively that for demolding, it is advantageous to have small features, inclined sidewalls, rounded corners, and a large radius of rotation. The dominant effect for nanostructures is adhesion, whereas for microstructures, it is friction. Moreover, demolding by tilting (step-and-repeat) exerts less stress on the imprint than demolding using a roll-to-roll approach. Finally, we present a 3D demolding simulation that identifies the most vulnerable positions of a geometry. From the lessons learned from our filling and demolding simulations, we could demonstrate the defect-free roll-to-roll UV nanoimprinting of a challenging pattern (cuboids with vertical sidewalls).