Understanding how alkaline treatment affects bamboo

In China, bamboo is a symbol of longevity and vitality, able to survive the hardest natural conditions and remain green all year round. In a storm, bamboo stems bend but do not break, representing the qualities of durability, strength, flexibility and resilience1.

Bamboo is a traditional construction material in Asia. Its strength and flexibility arise from its hollow stems (‘culms’) made from distinct material components. The solid outer shell of the culm is made primarily from longitudinal fibres. A higher density at the outer wall makes it stronger than the inner regions, and results in remarkable stiffness and flexural strength. Running through the centre of bamboo stem are parenchyma cells that store and channel the plant’s nutrients.

At the micro-/nano-scale both the fibres and the matrix contain cellulose nano-fibrils of the same type. However, the structural arrangement of the two materials result in contrasting mechanical properties. Individual fibres may reach a strength of 900 MPa, whilst the matrix can only resist about 50 MPa. There is also a considerable difference in their elastic properties, with the fibres being much stiffer than the matrix.

Bamboo is often treated with alkaline solutions, to modify these properties. Alkaline treatments can turn this rapidly renewable and low-cost resource into soft textiles, and extract fibres to be used in composite materials or as biomass for fuel.

>Read more on the Diamond Light Source website

Image: Dr Enrico Salvati on the B16 beamline at Diamond.

Major upgrade of the NCD beamline

The NCD beamline, now NCD-SWEET, devoted to Small Angle and Wide Angle X-ray Scattering (SAXS, WAXS), is offering users further experimental possibilities and higher quality data.

The SAXS beamline of ALBA has gone through a major upgrade in 2017. Upgraded items in the SAXS WAXS experimental techniques (SWEET) involve a new monochromator system, a new photon counting detector (Pilatus 1M), a new sample table with an additional rotating stage, and a beam conditioning optics with µ-focus and GISAXS options.

The original double crystal monochromator (DCM) has been replaced by a channel-cut silicon (1 1 1), improving the beam stability at sample position up to 0.9% and 0.4% of the beam size horizontally and vertically, respectivelly.

>Read more on the ALBA website

Figure: Vertical beam profile with the Be lenses into the beam (Horizontal axis unit is mm). The plot is the derivative of an edge scan along the vertical direction. The horizontal beam profile shows a gaussian shape as well.

Modifications to novel non-fullerene small molecule acceptor in organic thin film

… for solar cells demonstrates improved power conversion efficiency.

Scientists from the Imperial College London, Monash University, CSIRO, and King Abdullah University of Science and Technology have reported an organic thin film for solar cells with a non-fullerene small molecule acceptor that achieved a power conversion efficiency of just over 13 per cent.

By replacing phenylalkyl side chains in indacenodithieno[3,2-b]thiophene-based non-fullerene acceptor (ITIC) with simple linear chains to form C8-ITIC, they improved the photovoltaic performance of the material.

C8-ITIC was blended with a fluorinated analog of the donor polymer PBDB-T to form bulk-heterojunction thin films.

The research was recently published in Advanced Materials.

Dr Xuechen Jiao of McNeill Research Group at Monash University carried out grazing incidence wide angle X-ray scattering (GIWAXS) measurements at the Australian Synchrotron to gain morphological information on pure and blended thin films.

“By changing the chemical structure of the organic compound, a promising boost in efficiency was successfully achieved in an already high-performing organic solar cells” said Jiao.

>Read more on the Australian Synchrotron website