Reorientation of π-conjugated molecules on few-layer MoS2 films

We show that small π-conjugated molecules adopt a lying-down orientation when deposited on few-layer MoS2 with horizontally oriented layers. In contrast, for vertically aligned MoS2 layers, DIP molecules are arranged in a standing-up manner.

Structural changes of block copolymers with bi-modal orientation under fast cyclical stretching as observed by synchrotron SAXS

Here we examine a block copolymer with cylindrical morphology having a bio-inspired microstructure of anisotropic orthogonally oriented layers and report changes of the microstructure under uniaxial strain.

Phenyl acridine-9-carboxylate

The acridine ring system and the benzene ring in the title compound, C20H13NO2, are oriented at a dihedral angle of 6.4 (2)°. The carboxyl group is twisted at an angle of 83.6 (2)° relative to the acridine skeleton. The molecules in the crystal are arranged in stacks along thebaxis, with two of the acridine rings involved in multiple π–π interactions [centroid–centroid distances in the range 3.536 (2)–3.894 (2) Å]. Stacks arranged parallel are linkedviaC—H...π interactions, forming layers in theacplane that are in contact with adjacent, inversely oriented layersviaother C—H...π interactions, giving rise to double layers. The inversely oriented double layers interact dispersively. The acridine units are parallel within the parallel-oriented stacks, but inclined at an angle of 79.6 (2)° in the inversely oriented stacks.

Effects of systematic variation of wood adherend bending stiffness on fracture properties: Part 1. Influence of grain angle

When wood beams are bonded to form double cantilever beam (DCB) specimens, the resulting fracture properties are often quite scattered. Random variations of properties of wood are usually considered as the reason for the data scatter, but there are also morphological aspects that can possibly be accounted for. The present paper focuses on these morphological aspects and, in particular, an analytical model has been developed for evaluating how the orientation and stiffness of the layers of beams of constant cross section influences the stiffness variation of the beam along its length. Wood in DCBs is a common example of a material with oriented layers resulting from the alternating earlywood (EW) and latewood (LW). Part of the paper is dedicated to Douglas fir (Pseudotsuga menziesii), where the variability of equivalent elastic stiffness is found to be on the order of ±6–8% in bonded DCBs, depending on grain orientation. Other representative cases of bonded wood beams are also presented, where the stiffness variability is on the order of ±15–20%. Part 2 of this paper will evaluate how these levels of elastic stiffness variations influence the measured critical strain energy release rate, .