Side-on liquid crystal polyacrylate in Langmuir-Blodgett films

A side-on fixed liquid crystal polyacrylate has been investigated in Langmuir and Langmuir-Blodgett (LB) films. High in-plane orientation of the mesogenic groups has been observed within the LB multilayers, showing the ability of the LB technique to align a liquid crystal. The analysis of the in-plane order versus the dipping speed suggests some self-aggregation of the polymer in the monolayer. Within these aggregates, the molecular orientation (in-plane and out-plane) has been deduced from infrared dichroism experiments; the mesogenic group lies mainly parallel to the dipping direction and relatively flat on the substrate. This alignment of the polymer is however partially lost with time, leading to materials with less in-plane anisotropy.     

Shape-tunable polymer nodules grown from liposomes via ring-opening metathesis polymerization

A new inisurf (acting as surfactant and initiator) molecule for ring-opening metathesis polymerization (ROMP) was synthesized and used in aqueous solution in order to control the size and shape of polymer nodules grown from liposomes. Nodules were observed to grow in size with conversion of monomer, and depending on the monomer used, they adopted either a spherical or comet-like shape. Here, we investigate polymer production from a liposome surface. We use a hydrophobic derivative of the Grubbs catalyst positioned at the liposome surface to allow for ROMP of monomers dissolved in the aqueous outer phase. We obtain nodules of polymer that can grow up to tens of micrometers, unveiling new efficient possibilities of polymerization from a membrane in an aqueous solution.     

Importance of the Correlation between Width and Length in the Shape Analysis of Nanorods: Use of a 2D Size Plot To Probe Such a Correlation

Analysis of nanoparticle size through a simple 2D plot is proposed in order to extract the correlation between length and width in a collection or a mixture of anisotropic particles. Compared to the usual statistics on the length associated with a second and independent statistical analysis of the width, this simple plot easily points out the various types of nanoparticles and their (an)isotropy. For each class of nano‐objects, the relationship between width and length (i.e., the strong or weak correlations between these two parameters) may suggest information concerning the nucleation/growth processes. It allows one to follow the effect on the shape and size distribution of physical or chemical processes such as simple ripening. Various electron microscopy pictures from the literature or from the authors′ own syntheses are used as examples to demonstrate the efficiency and simplicity of the proposed 2D plot combined with a multivariate analysis.     

Langmuir–Blodgett Films of Single-Molecule Nanomagnets

Magnetic Langmuir–Blodgett films containing well-organized monolayers of single-molecule magnets are reported. The single-molecule magnets in question are high-spin molecular clusters of the type [Mn₁₂O₁₂(carboxylate)₁₆]. The structure of such multilayered inorganic–organic composites is depicted schematically in the figure.