Synthetic polymer forms double helix with high stiffness
- PDF / 629,312 Bytes
- 1 Pages / 585 x 783 pts Page_size
- 97 Downloads / 167 Views
NMR spectrum and the diffraction pattern. The researchers also used spectroscopic methods to investigate the dynamics and alignment of the helix, which supported their findings using molecular dynamics simulations. The self-assembly of PBDT, driven by enthalpic and entropic effects that result from electrostatic repulsions, hydrophobic stacking of phenyl groups, and interactions between amide groups, occurs within 30 ns (see Figure). Gustav Nyström, head of the Laboratory for Cellulose & Wood Materials at Empa— Swiss Federal Laboratories for Materials Science and Technology, emphasizes that “the results are interesting since the PBDT double helix reaches unusually long persistence lengths approaching those of the 2 µm rigid segments of nanocellulose fibrils, and 1–3 µm regions of amyloid fibrils. This observation suggests that these helical assemblies may, in common with nanocellulose or amyloids, be interesting as building blocks for functional composite materials.” Nyström is also looking forward to a deeper look into the assembly mechanism and the interactions at play with PBDT. Coincidently, these are two directions the research team led by Madsen, Qiao, and Dingemans are taking. In addition to investigating the molecular interactions, they are also “making controlled changes to the PBDT molecular structure and to the synthesis protocols to study how long the persistence length can be, what are the key interactions and how the helix originally forms,” says Madsen. “Our team is also pursuing many other avenues related to the PBDT rods, such as making ionic composite electrolytes with high stiffness and liquid-like ionic conductivity, and structural composites with high strength and small filler amounts.” Indeed, one advantage of using synthetic chemistry over using biological fibers is the possibility of obtaining large quantities using inexpensive and scalable chemical reactions. Madsen further explains that “it is very easy to make 10–100 g quantities in the lab from inexpensive starting materials that are commercially available. We expect we can very easily scale this up to kg quantities.” Hortense Le Ferrand
• VOLUME • MAY MRS BULLETINCore 2019 • www.mrs.org/bulletin Downloaded from https://www.cambridge.org/core. IP address: 5.189.202.12, on 12 Aug 2019 at 12:03:48, subject to the Cambridge terms 44 of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1557/mrs.2019.110
327
Data Loading...
