4 research outputs found
Room Temperature Synthesis of a Covalent Monolayer Sheet at Air/Water Interface Using a Shape-Persistent Photoreactive Amphiphilic Monomer
The
shape-persistent monomer <b>3</b> with its three 1,8-diazaanthracene
(DAA) units is spread and compressed at the air/water interface and
the layer then converted into a 1.5 nm thick covalent monolayer sheet
by photoirradiation under ambient conditions. The sheet obtained under
these extremely mild conditions is mechanically stable to carry its
own weight when spanned over TEM grids. While its molecular structure
cannot be given yet with certainty, it is likely to be the result
of [4 + 4]-cycloaddition dimerizations between the DAA units of neighboring
monomers. Evidence is based on the wavelength of the monomer fluorescence
emission, the kinetics of this emission’s intensity decay with
irradiation time, and the mechanical sheet stability that suggests
a surpassing of percolation threshold. Finally, the thermal stability
of the sheet is investigated
Large Area Synthesis of a Nanoporous Two-Dimensional Polymer at the Air/Water Interface
We present the synthesis
of a two-dimensional polymer at the air/water interface and its nm-resolution
imaging. Trigonal star, amphiphilic monomers bearing three anthraceno
groups on a central triptycene core are confined at the air/water
interface. Compression followed by photopolymerization on the interface
provides the two-dimensional polymer. Analysis by scanning tunneling
microscopy suggests that the polymer is periodic with ultrahigh pore
density
Polydopamine Films from the Forgotten Air/Water Interface
The
formation of polydopamine under mild oxidation conditions from
dopamine solutions with mechanical agitation leads to the formation
of films that can functionalize all kinds of materials. In the absence
of stirring of the solution, we report the formation of polydopamine
films at the air/water interface (PDA A/W) and suggest that it arises
from an homogeneous nucleation process. These films grow two times
faster than in solution and can be deposited on hydrophilic or hydrophobic
substrates by the Langmuir–Schaeffer technique. Thanks to this
new method, porous and hydrophobic materials like polytetrafluoroethylene
(PTFE) membranes can be completely covered with a 35 nm thick PDA
A/W film after only 3h of reaction. Finally the oxidation of a monomer
followed by a polymerization in water is not exclusive to polydopamine
since we also transferred polyaniline functional films from the air/water
interface to solid substrates. These findings suggest that self-assembly
from a solution containing hydrophilic monomers undergoing a chemical
transformation (here oxidation and oligomerization) could be a general
method to produce films at the liquid/air interface
A Two-Dimensional Polymer from the Anthracene Dimer and Triptycene Motifs
A two-dimensional
polymer (2DP) based on the dimerization of anthraceno
groups arranged in a triptycene motif is reported. A photoinduced
polymerization is performed in the crystalline state and gives a lamellar
2DP via a crystal-to-crystal (but not single-crystal to single-crystal)
transformation. Solvent-induced exfoliation provides monolayer sheets
of the 2DP. The 2DP is considered to be a tiling, a mathematical approach
that facilitates structural elucidation