Nanoscale & Nanoscale Advances Blog

Scientists from Italy, the UK, Belgium and France provide insights into the efficiency of pyrene sulfonic sodium salts for the preparation of graphene in their recent Nanoscale paper, and clarify the role of different molecular properties on graphene exfoliation.

They compared pyrene derivatives with increasing number of sulfonic groups for their efficiency as exfoliating agents in the preparation of graphene. They combined different experimental and modelling techniques to find a correlation between the graphene-pyrene dye interaction, the molecular structure and the amount of graphene flakes solubilised. They found that a large dipole and molecular asymmetry are important for adsorption of the dye molecule on graphene. The dipole allows the molecule to “slide” into the solvent layer between the graphene surface and the aromatic core of the dye, and displace the water molecules.

The efficiency of pyrene derivatives in exfoliating graphene is well known, but the details of their interactions with graphene have been somewhat unclear so far. An understanding of these interactions is important for developing the processability of graphene, which holds great potential for technological applications in numerous fields.

Read this HOT article today:

Nanoscale insight into the exfoliation mechanism of graphene with organic dyes: effect of charge, dipole and molecular structure
Andrea Schlierf, Huafeng Yang, Elias Gebremedhn, Emanuele Treossi, Luca Ortolani, Liping Chen, Andrea Minoia, Vittorio Morandi, Paolo Samorì, Cinzia Casiraghi, David Beljonne and Vincenzo Palermo
DOI: 10.1039/C3NR00258F

In their recent Nanoscale Communication, Borsali et al. varied the composition of the annealing co-solvent in order to control the orientation of nanocylinders in sugar-based block copolymer thin films. Their method, which achieves nanopatterning in three dimensions, could have important applications in next-generation nanoelectronics.

The group have developed a novel class of natural-synthetic “hybrid” block copolymer, where one of the blocks consists of poly- or oligosaccharides. The rod-like structures formed by the saccharide blocks further sterically increase the incompatibility of the hydrophobicity-hydrophilicity imbalance of the saccharide and synthetic polymer blocks.  The authors used H₂O -THF mixtures as the annealing solvent system, since the saccharide component of the polymer is soluble in H₂O, but not in THF, and vice versa for the other block polymer component. By changing the composition of the H₂O-THF mixture, the orientation of the cylinder domain in the block copolymer thin film on a silicon substrate was successfully controlled from horizontal to perpendicular.

Read this HOT Nanoscale communication today:

Control of 10 nm scale cylinder orientation in self-organized sugar-based block copolymer thin films
Issei Otsuka, Salomé Tallegas, Yoko Sakai, Cyrille Rochas, Sami Halila, Sébastien Fort, Ahmad Bsiesy, Thierry Baron and Redouane Borsali
DOI: 10.1039/C3NR00332A

Wenping Lv and Ren’an Wu from the Dalian Institute of Chemical Physics have investigated the aggregation of two graphene nanosheets in water and the role of the interfacial water monolayer in the aggregation mechanism.

They found that the interfacial water monolayers hinder the aggregation of graphene nanosheets, attributed to the many  structurally ordered H-bonds of the water monolayer. Their findings advance understanding of the hydrophobic assembly of nanomaterials, such as proteins in aqueous solution.

Read this Nanoscale paper in full:

The interfacial-organized monolayer water film (MWF) induced “two-step” aggregation of nanographene: both in stacking and sliding assembly pathways
Wenping Lv and Ren’an Wu
DOI: 10.1039/C3NR33447C

Gold nanoparticles functionalised with aptamers have been found to be highly effective inhibitors for human immunodeficiency virus type 1 reverse transcriptase. The nanoparticles particles have been shown to reduce the ability of the HIV virus to reproduce and infect new cells.

The scientists behind the work describe how inhibition is enhanced further by using combinations of different aptamers that each target different parts of the virus.

Find out more about this exciting work – read the Nanoscale article today:

Highly efficient inhibition of human immunodeficiency virus type 1 reverse transcriptase by aptamers functionalized gold nanoparticles
Yen-Chun Shiang, Chung-Mao Ou, Shih-Ju Chen, Ting-Yu Ou, Han-Jia Lin, Chih-Ching Huang and Huan-Tsung Chang
DOI: 10.1039/C3NR33403A

This very exciting issue on self propelled nano and microsystems, containing many contributions from leading groups around the globe, was guest edited by Martin Pumera and Samuel Sanchez.