331 research outputs found
Digital transformation in materials science: A paradigm change in material's development
The ongoing digitalization is rapidly changing and will further revolutionize all parts of life. This statement is currently omnipresent in the media as well as in the scientific community; however, the exact consequences of the proceeding digitalization for the field of materials science in general and the way research will be performed in the future are still unclear. There are first promising examples featuring the potential to change discovery and development approaches toward new materials. Nevertheless, a wide range of open questions have to be solved in order to enable the soâcalled digitalâsupported material research. The current stateâofâtheâart, the present and future challenges, as well as the resulting perspectives for materials science are described.The ongoing expansion of digitalization approaches influences the material research significantly. The complete workflow of the development of novel materials, from synthesis, over characterization, to fabrication will change within the coming years to a more automatic, dataâdriven, and robotâbased approach. The current status is summarized and advantages, challenges, and future perspectives discussed
Selective metalâcomplexation on polymeric templates and their investigation via isothermal titration calorimetry
Selective complexation of metal ions represents a powerful tool for the development of versatile supramolecular architectures. While research in the field of molecular devices and machinery is sophisticated, the selective formation of metal complexes is not prevalent in polymer chemistry. Thus, the implementation of orthogonal binding concepts into a polymeric matrix is presented. In this context, an endâfunctionalized poly( N âisopropylacrylamide) (PNIPAm) carrying zincâporphyrin (ZnTPP) as well as a terpyridine (tpy) ligand side by side is utilized. With these binding sites, the polymer can simultaneously interact with a pyridine moiety via a ZnTPP interaction and a terpyridine unit by the formation of a bisâterpyridine complex. The complexation behavior of this polymer and different model compounds is intensively investigated by isothermal titration calorimetry. The obtained results indicate that the reported orthogonality of these two systems is successfully transferred into a functional polymeric architecture
Comparing Microwave and Classical Synthesis of Oxymethylene Dimethyl Ethers
Polyoxymethylene dimethyl ethers (OME n ) are considered as substituents or additives for fossil diesel fuel. Efficiency of the synthesis is crucial for the development of industrial scale production plants. Therefore, the design of suitable catalysts and the efficient heating play important roles in OME fuel synthesis. In this work, microwaveâassisted synthesis (MAS) is carried out and compared to a classical approach using standard thermal heating. Different polymeric materials, e.g., Amerlyst15, are utilized as catalysts, and screened for the catalytic synthesis of OME. Within this approach, the kinetics of the reaction are analyzed in detail
Quantification of tripleâshape memory behavior of polymers utilizing tension and torsion
Abstract Shapeâmemory polymers (SMPs) are well investigated smart materials. With their ability to memorize their original shape they are interesting candidates for a large range of applications. Certain SMPs feature triple shapeâmemory behavior. In these cases, it is possible to fix two different temporary shapes. However, the exact quantification of the individual steps regarding their programming and recovery rate is difficult and has not been possible so far. In this work, a novel approach for the analysis and exact quantification of triple SMPs is presented. By applying a customized rheology protocol, it is possible to perform and to analyze torsional and tensional experiments simultaneously. Consequently, different shapes in different directions (vertical and horizontal) can be fixed and the individual steps can be investigated independently at different switching temperatures
Exploring the principles of self-healing polymers based on halogen bond interactions
In this study, novel self-healing polymers based on halogen bonds as reversible supramolecular crosslinking moieties are presented. The reversible crosslinking is facilitated by a polymer-bound bidentate halogen bond donor entity in combination with small molecule acceptor suberic acid. The binding strength of the crosslinking can be tuned via deprotonation of the diacid crosslinker. The material characteristics are investigated with several methods such as NMR and Raman spectroscopy, thermogravimetric analysis and differential scanning calorimetry as well as rheology. The tactile profile measurements have been utilized to monitor the scratch healing ability of the polymer networks revealing excellent healing efficiencies up to 99% within 2 h at a temperature of 100°C. Thus, the self-healing ability of halogen bond polymers could be quantified for the first time
Recommended from our members
Shape-Memory Metallopolymer Networks Based on a TriazoleâPyridine Ligand
Shape memory polymers represent an interesting class of stimuli-responsive polymers. With their ability to memorize and recover their original shape, they could be useful in almost every area of our daily life. We herein present the synthesis of shape-memory metallopolymers in which the switching unit is designed by using bis(pyridineâtriazole) metal complexes. The polymer networks were synthesized via free radical polymerization of methyl-, ethyl- or butyl-methacrylate, tri(ethylene glycol) dimethacrylate and a methacrylate moiety of the triazoleâpyridine ligand. By the addition of zinc(II) or cobalt(II) acetate it was possible to achieve metallopolymer networks featuring shape-memory abilities. The successful formation of the metal-ligand complex was proven by Fourier transform infrared (FT-IR) spectroscopy and by 1H NMR spectroscopy. Furthermore, the shape-recovery behavior was studied in detailed fashion and even triple-shape memory behavior could be revealed
Synthesis and Characterization of Metallopolymer Networks featuring Triple Shape-Memory Ability Based on Different Reversible Metal Complexes
This study presents the synthesis and characterization of metallopolymer networks with a triple shape-memory ability. A covalently crosslinked polymer network featuring two different additional ligands in its side chains is synthesized via free radical polymerization (FRP). The subsequent addition of different metal salts leads to the selective formation of complexes with two different association constants ( K a ), proven via isothermal titration calorimetry (ITC). Those two supramolecular crosslinks feature different activation temperatures and can act as two individual switching units enabling the fixation and recovery of two temporary shapes. The presented samples were investigated in a detailed fashion via differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and FT-Raman spectroscopy. Furthermore, thermo-mechanical analyses (TMA) revealed excellent dual and triple shape-memory abilities of the presented metallopolymer networks
Shape-Memory Metallopolymers Based on Two Orthogonal MetalâLigand Interactions
A new shape-memory polymer is presented, in which both the stable phase as well as the switching unit consist of two different metal complexes. Suitable metal ions, which simultaneously form labile complexes with histidine and stable ones with terpyridine ligands, are identified via isothermal titration calorimetry (ITC) measurements. Different copolymers are synthesized, which contain butyl methacrylate as the main monomer and the metal-binding ligands in the side chains. Zn(TFMS)2 and NiCl2 are utilized for the dual crosslinking, resulting in the formation of metallopolymer networks. The switching temperature can simply be tuned by changing the composition as well as by the choice of the metal ion. Strain fixity rates (about 99%) and very high strain recovery rates (up to 95%) are achieved and the mechanism is revealed using different techniques such as Raman spectroscopy. © 2021 The Authors. Advanced Materials published by Wiley-VCH Gmb
- âŠ