10 research outputs found
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The Localization Behavior of Different CNTs in PC/SAN Blends Containing a Reactive Component
Co-continuous blend systems of polycarbonate (PC), poly(styrene-co-acrylonitrile) (SAN), commercial non-functionalized multi-walled carbon nanotubes (MWCNTs) or various types of commercial and laboratory functionalized single-walled carbon nanotubes (SWCNTs), and a reactive component (RC, N-phenylmaleimide styrene maleic anhydride copolymer) were melt compounded in one step in a microcompounder. The blend system is immiscible, while the RC is miscible with SAN and contains maleic anhydride groups that have the potential to reactively couple with functional groups on the surface of the nanotubes. The influence of the RC on the localization of MWCNTs and SWCNTs (0.5 wt.%) was investigated by transmission electron microscopy (TEM) and energy-filtered TEM. In PC/SAN blends without RC, MWCNTs are localized in the PC component. In contrast, in PC/SAN-RC, the MWCNTs localize in the SAN-RC component, depending on the RC concentration. By adjusting the MWCNT/RC ratio, the localization of the MWCNTs can be tuned. The SWCNTs behave differently compared to the MWCNTs in PC/SAN-RC blends and their localization occurs either only in the PC or in both blend components, depending on the type of the SWCNTs. CNT defect concentration and surface functionalities seem to be responsible for the localization differences
Industry-Scale Orchestrated Federated Learning for Drug Discovery
To apply federated learning to drug discovery we developed a novel platform
in the context of European Innovative Medicines Initiative (IMI) project
MELLODDY (grant n{\deg}831472), which was comprised of 10 pharmaceutical
companies, academic research labs, large industrial companies and startups. The
MELLODDY platform was the first industry-scale platform to enable the creation
of a global federated model for drug discovery without sharing the confidential
data sets of the individual partners. The federated model was trained on the
platform by aggregating the gradients of all contributing partners in a
cryptographic, secure way following each training iteration. The platform was
deployed on an Amazon Web Services (AWS) multi-account architecture running
Kubernetes clusters in private subnets. Organisationally, the roles of the
different partners were codified as different rights and permissions on the
platform and administrated in a decentralized way. The MELLODDY platform
generated new scientific discoveries which are described in a companion paper.Comment: 9 pages, 4 figures, to appear in AAAI-23 ([IAAI-23 track] Deployed
Highly Innovative Applications of AI
Ultrathin structures derived from interfacially modified polymeric nanocomposites to curb electromagnetic pollution
The use of electronic devices and wireless networks is increasing rapidly, and electromagnetic (EM) pollution remediation remains a challenge. We employed a unique approach to fabricate two ultrathin (approx. 53 μm) multilayered assemblies to address this. By sequentially stacking thin films of polyvinylidene difluoride (PVDF) and polycarbonate (PC) nanocomposites and interfacially locking them with a mutually miscible polymer (PMMA, polymethyl methacrylate), materials with enhanced structural properties and electromagnetic interference (EMI) shielding performance can be designed. Utilizing reduced graphene oxide (rGO) and molybdenum disulfide (MoS2) as a template, ferrite was grown on the surface to design two different nanohybrid structures (rGO–Fe3O4 and MoS2–Fe3O4). PVDF was composited with either rGO–Fe3O4 or MoS2–Fe3O4, and multiwall carbon nanotubes (CNTs) were dispersed in the PC component. As PC and PVDF are immiscible, their poor interface would result in inferior structural properties, which can be challenging in designing EMI shielding materials due to cyclic thermal fatigue. Hence, PMMA is sandwiched to interfacially stitch the components (PC and PVDF) and improve interfacial adhesion. This was confirmed using SEM/EDS and Raman mapping/imaging. The mechanical stability of the multilayered assemblies was characterized using a dynamic mechanical analyzer (DMA), and the storage modulus was found to be as high as 2767 MPa at 40 °C (@constant frequency and strain amplitude), for the multilayered film with rGO–Fe3O4 in PVDF, PMMA as a sandwich layer and CNTs in PC. A typical assembly of 9 multilayers (∼480 μm) with rGO–Fe3O4 in PVDF, and CNTs in PC, and interfacially stitched with PMMA gave rise to a high EMI shield effectiveness (SET) of −26.3 dB @ 26.5 GHz. This unique arrangement of a multilayered assembly suppressed EMI primarily by absorption
The effect of gold nanoparticles size and hydrophobicity on the morphology evolution and orientation of PPMA-b-PMMA block copolymer thin films
Nanoporous Cathodes for High-Energy Li–S Batteries from Gyroid Block Copolymer Templates
This study reports on a facile approach to the fabrication of nanoporous carbon cathodes for lithium sulfur batteries using gyroid carbon replicas based on use of polystyrene-poly-4-vinylpyridine (PS-P4VP) block copolymers as sacrificial templates. The free-standing gyroid carbon network with a highly ordered and interconnected porous structure has been fabricated by impregnating the carbon precursor solution into the gyroid block copolymer nanotemplates and subsequently carbonizing them. A wide range of analytical tools have been employed to characterize fabricated porous carbon material. Prepared nanostructures are envisioned to have a great potential in myriad areas such as energy storage/conversion devices owing to their fascinating morphology exhibiting high surface area and uniform porosity with interconnected three-dimensional networks. The resulting carbon nanoporous structures infused with elemental sulfur have been found to work as a promising electrode for lithium sulfur batteries demonstrating a high cycling stability over more than 200 cycles
Synthesis of High-Crystallinity DPP Polymers with Balanced Electron and Hole Mobility
We review the Stille coupling synthesis
of P(DPP2OD-T) (Poly[[2,5-di(2-octyldodecyl)pyrrolo[3,4-<i>c</i>]pyrrole-1,4(2<i>H</i>,5<i>H</i>)-dione-3,6-diyl]-<i>alt</i>-[2,2′:5′,2″-terthiophene-5,5″-diyl]])
and show that high-quality, high molecular weight polymer chains are
already obtained after as little as 15 min of reaction time. The results
of UV–vis spectroscopy, grazing incidence wide-angle X-ray
scattering (GIWAXS), and atomic force microscopy show that longer
reaction times are unnecessary and do not produce any improvement
in film quality. We achieve the best charge transport properties with
polymer batches obtained from short reaction times and demonstrate
that the catalyst washing step is responsible for the introduction
of charge-trapping sites for both holes and electrons. These trap
sites decrease the charge injection efficiency, strongly reducing
the measured currents. The careful tuning of the synthesis allows
us to reduce the reaction time by more than 100 times, achieving a
more environmentally friendly, less costly process that leads to high
and balanced hole and electron transport, the latter being the best
reported for an isotropic, spin-coated DPP polymer