Materials

Materials

chaired by Jurriaan Huskens & Gertjan Koster

Abstracts

Inkjet printing of MnO2 nanosheets for flexible micro-supercapacitors, Yang Wang (IMS)

To meet the trends in the electronics industry towards being miniature, portable, and highly integrated, new energy-storage units are in urgent demand. Supercapacitors are an emerging class of energy storage devices that holds great promise for future electronic systems due to their superior power density, stability and cycle life compared with batteries. In particular, micro-supercapacitors with in-plane structure are attracting a lot of attention. Inkjet printing is considered as a promising technique for micro-supercapacitors fabrication owing to its simple, versatile, environmental-friendly and low-cost features. Here we prepared an ink containing two-dimensional δ-MnO2 nanosheets with an average lateral size of 89 nm and a sheet thickness around 1 nm. By engineering the ink formulation of δ-MnO2 ink, we were able to inkjet print on arbitrary substrates to form δ-MnO2 patterns and without undesired “coffee-ring” effect. All-solid-state symmetrical micro-supercapacitors based on PEDOT: PSS and δ-MnO2 nanosheets materials were fabricated by inkjet printing. The fabricated micro-supercapacitors showed excellent flexibility and good cycling stability. The micro-supercapacitors attained the highest volumetric capacitance of 2.4 F cm-3, and an energy density of 1.8 ×10-4 Wh cm-3 at a power density of 0.018 W cm-3, which is comparable with other devices.

Looking under the surface with sub-nm resolution, I.A. Makhotkin (XUV)

A comprehensive understanding of nano objects generally requires the researcher to connect all information on the object’s growth, its internal structure and its functional properties. X-ray reflectivity, diffraction and scattering are non-destructive techniques capable of providing a full structural characterization. However, the more complex the structure to be analyzed, the more advanced the mathematics and the algorithms need to be. For the analysis of the structure of 1D nano objects – ultrathin films and periodic multilayers – we have developed a full measurement platform based on a combination of X-ray reflectivity and X-ray fluorescence, and driven by a model independent data analysis method. For 2D and 3D ordered nano objects, we are exploring the analytical power of X-ray scattering and diffraction techniques with the aim to enable routine analysis, leading to equally complete data sets.

Preparing the next-generation of sustainable membranes: aqueous phase separation using weak polyelectrolytes, Joshua Willott (MST)

While membranes are often used for environmental friendly applications, their production processes rely on environmentally unfriendly, expensive and toxic organic solvents such as N-Methyl-pyrrolidone (NMP) or dimethylformamide (DMF). For this, polymers are first dissolved in NMP/DMF (the solvent), while solvent exchange with water (the non-solvent) leads to a quick phase inversion, that traps the desired porous membrane structure. In this research project the goal is to design a highly novel approach to produce membranes without the need of organic solvents. This is done by precipitating water-soluble polymers in a controlled manner. By tuning the kinetic parameters of the precipitation process we can obtain both dense and porous structures which allows us to make membranes suitable for different applications. With this method we aim to demonstrate that our novel system can be a viable alternative to start producing membranes in a safer and more sustainable way.

Dynamic control of chiral liquid crystalline materials by light-driven molecular motors, Federico Lancia (BNT-BSM)

Light-responsive cholesteric liquid crystals can be formed by the incorporation of molecular motors in nematic liquid crystals. These motors have a non-planar, helical structure. Their irradiation with light fuels their unidirectional rotation which is dependent on their helicity. Used as chiral dopants in nematic liquid crystals, molecular motors mediate the formation of tight supramolecular helices, and their photo-activation induces large pitch modifications [1], a reorientation of the cholesteric axis [2], helix inversion [3], and continuous rotation of patterns under out-of-equilibrium conditions[4]. These unique properties have proven instrumental in designing dynamic systems before [4], while remaining limited by the lack of stability of each of the intermediate forms of the motor. Here, we show how new designs of molecular motors having different helical shapes, and different rotation speeds can be used to provide a range of dynamic features in liquid crystal materials, including the multistep photo-tuning of the cholesteric helix.