Single-crystal linear polymers through visible light-triggered topochemical quantitative polymerization.

One of the challenges in polymer science has been to prepare large-polymer single crystals. We demonstrate a visible light-triggered quantitative topochemical polymerization reaction based on a conjugated dye molecule. Macroscopic-size, high-quality polymer single crystals are obtained.

In situ Materials Characterization using the Tissue Diagnostic Instrument.

An understanding of the mechanical behavior of polymers is critical towards the design, implementation, and quality control of such materials. Yet experiments and method for the characterization of material properties of polymers remain challenging due the need to reconcile constitutive assumptions with experimental conditions. Well-established modes of mechanical testing, such as unconfined compression or uniaxial tension, require samples with specific geometries and carefully controlled orientations.

Hierarchical assembly of the siliceous skeletal lattice of the hexactinellid sponge Euplectella aspergillum.

Despite its inherent mechanical fragility, silica is widely used as a skeletal material in a great diversity of organisms ranging from diatoms and radiolaria to sponges and higher plants. In addition to their micro- and nanoscale structural regularity, many of these hard tissues form complex hierarchically ordered composites. One such example is found in the siliceous skeletal system of the Western Pacific hexactinellid sponge, Euplectella aspergillum.