On the dimensional control of 2D hybrid nanomaterials

Thermotropic smectic liquid crystalline polymers were used as a scaffold to create organic/inorganic hybrid layered nanomaterials. Different polymers were prepared by photopolymerizing blends of a hydrogen bonded carboxylic acid derivative and a 10 % cross-linker of variable length in their liquid crystalline phase. Nanopores with dimensions close to 1 nm were generated by breaking the hydrogen bonded dimers in a high pH solution. The pores were filled with positively charged silver (Ag) ions, resulting in a layered silver(I)-polymeric hybrid material. Subsequent exposure to a NaBH4 reducing solution allowed for the formation of supported hybrid metal/organic films. In the bulk of the film the dimension of the Ag nanoparticles (NPs) was regulated with subnanometer precision by the cross-linker length. Ag nanoparticles with an average size of 0.9, 1.3, and 1.8 nm were produced inside the nanopores thanks to the combined effect of spatially confined reduction and stabilization of the nanoparticles by the polymer carboxylic groups. At the same time, strong Ag migration occurred in the surface region, resulting in the formation of a nanostructured metallic top layer composed of large (10–20 nm) NPs.</p

Two-dimensional pH-responsive printable smectic hydrogels

Anisotropic swelling and deswelling of smectic liquid crystal networks have been observed in response to pH changes

Nanoporous membranes based on liquid crystalline polymers

In the present review, we discuss the most significant recent developments in the field of nanoporous membranes based on liquid crystalline lyotropic and thermotropic polymer networks

Nanoporous membranes based on liquid crystalline polymers

In the present review, we discuss the most significant recent developments in the field of nanoporous membranes based on liquid crystalline lyotropic and thermotropic polymer networks

Selective absorption of hydrophobic cations in nanostructured porous materials from cross-linked hydrogen-bonded columnar liquid crystals

A nanostructured porous material is obtained by crosslinking of a self-assembled system consisting of columnar liquid crystals with polyamines and removal of the template. For this purpose, a columnar liquid crystal with liquid crystalline properties at room temperature is synthesized and fully characterized. The orthogonal self-assembly of the columnar liquid crystal with polyamines (i.e., PPI dendrimers) results in the formation of nanosegregated structures. When crosslinked by photopolymerization a nanostructured crosslinked material is obtained. Partial removal of the polyamine template leads to a nanostructured porous material, which is characterized and the absorbent properties are investigated. The polarity of the porous material is probed and the porous material is used for the selective absorption of cationic dye molecules

Responsive nanoporous smectic liquid drystal polymer networks as efficient and selective adsorbents

An efficient and selective porous nanostructured polymer adsorbent is prepared from smectic liquid crystals. The adsorption study is performed by using hydrophilic dyes as water pollutants. The anionic pore interior of the nanoporous polymer is able to selectively adsorb cationic methylene blue over anionic methyl orange. Even zwitter ionic rhodamine B could hardly be adsorbed due to the presence of the anionic group in this dye. The confined pore dimensions allow size selective adsorption; a 4th generation cationic dendrimer is not able to diffuse into the nanometer sized pores. The porous nature of the polymer provides easy and fast accessibility of all adsorption sites. Stoichiometric ion exchange is obtained, which equates to an adsorption capacity of nearly 1 gram of methylene blue per 1 gram adsorbent. A competitive Langmuir adsorption constant and pseudo second order rate constant are determined. The adsorbent and adsorbate could both be retrieved after acid treatment of the polymer

Responsive nanoporous smectic liquid drystal polymer networks as efficient and selective adsorbents

An efficient and selective porous nanostructured polymer adsorbent is prepared from smectic liquid crystals. The adsorption study is performed by using hydrophilic dyes as water pollutants. The anionic pore interior of the nanoporous polymer is able to selectively adsorb cationic methylene blue over anionic methyl orange. Even zwitter ionic rhodamine B could hardly be adsorbed due to the presence of the anionic group in this dye. The confined pore dimensions allow size selective adsorption; a 4th generation cationic dendrimer is not able to diffuse into the nanometer sized pores. The porous nature of the polymer provides easy and fast accessibility of all adsorption sites. Stoichiometric ion exchange is obtained, which equates to an adsorption capacity of nearly 1 gram of methylene blue per 1 gram adsorbent. A competitive Langmuir adsorption constant and pseudo second order rate constant are determined. The adsorbent and adsorbate could both be retrieved after acid treatment of the polymer

Effect of the ortho-alkylation of perylene bisimides on the alignment and self-assembly properties

The effect of the ortho alkylation of perylene bisimides on the alignment and self-assembly properties has been studied. It was found that the dichroic properties of perylene bisimides in a liquid crystal host can be reversed with a single synthetic step by ortho alkylation. Furthermore, a solvent-induced growth of ultralong organic n-type semiconducting fibrils from non-ortho-alkylated perylene bisimide was observed. Ortho substitution of the perylene bisimide core alters the mode of fibrillar growth, leading to isotropic crystallization