Transition of deformation modes from bending to auxetic compression in origami-based metamaterials for head protection from impact.

For the protection of the human head by energy absorption structures, a soft mechanical response upon contact with the head is required to mitigate the effect of impact, while a hard mechanical response for highly efficient energy absorption is required to stop the movement of the head. This study realized the opposite mechanical properties during head protection by transitioning the deformation mode from bending to auxetic compression. First, non-linear finite element (FE) models were constructed to numerically reproduce the bending behavior.

Wettability of Primer-Treated AlO Surfaces by Bisphenol A Diglycidyl Ether: Determination of the Mechanism from Molecular Dynamics Simulations and Experiments.

This study aims to develop a molecular dynamics (MD) simulation procedure to investigate the wettability of primer-treated AlO surfaces by bisphenol A diglycidyl ether (BADGE) and to understand the interaction between the surface and the liquid. The MD simulation results were compared with those obtained by contact angle measurements, time-of-flight secondary ion mass spectrometry (TOF-SIMS), and atomic force microscopy (AFM) and were found to be in agreement with the experimental evaluations. The results obtained from both the MD simulations and the experiments suggest that the configuration of the primers on the surface affect its wettability.

Enzymatic polymerization of coniferyl alcohol in the presence of cyclodextrins.

The dehydrogenative polymerization of coniferyl alcohol by horseradish peroxidase was performed in 0.10 M phosphate buffer at 27 degrees C. Dehydrogenative polymer (DHP) from coniferyl alcohol was characterized by size exclusion chromatography (SEC) and nuclear magnetic resonance (NMR) spectroscopy.

Side chain-directed assembly of triangular molecular panels into a tetrahedron vs. open cone.

Despite their structural similarity, triangular tetradentate ligands 2b and 2c experience different assembly pathways on complexation with (en)Pd(NO3)2 to give M8L4 tetrahedral (3) and open cone (4) structures, respectively, due to steric restriction by side chains at the corner or on the edge of the ligands.

Molecular Paneling by Coordination: An M L Hexahedral Molecular Capsule having Clefts for Reversible Guest Inclusion.

Only one positional isomer is obtained from the assembly of 21 small components. A triangular molecular panel with five coordination sites is assembled upon complexation with [Pd (en)] (en=ethylenediamine) into a unique M L hexahedral coordination capsule (see X-ray structure). The capsule can encapsulate/exchange organic guests reversibly through the clefts at the nonbinding sites of the capsule.