Rigid Urea and Self-Healing Thiourea Ethanolamine Monolayers

Abstract

A series of long-tail alkyl ethanolamine analogs containing amide-, urea-, and thiourea moieties was synthesized and the behavior of the corresponding monolayers was assessed on the Langmuir−Pockels trough combined with grazing incidence X-ray diffraction experiments and complemented by computer simulations. All compounds form stable monolayers at the soft air/water interface. The phase behavior is dominated by strong intermolecular headgroup hydrogen bond networks. While the amide analog forms well-defined monolayer structures, the stronger hydrogen bonds in the urea analogs lead to the formation of small three-dimensional crystallites already during spreading due to concentration fluctuations. The hydrogen bonds in the thiourea case form a two-dimensional network, which ruptures temporarily during compression and is recovered in a self-healing process, while in the urea clusters the hydrogen bonds form a more planar framework with gliding planes keeping the structure intact during compression. Because the thiourea analogs are able to self-heal after rupture, such compounds could have interesting properties as tight, ordered, and self-healing monolayers.

Synthesis of S-ligand tethered cellulose nanofibers for efficient removal of Pb(II) and Cd(II) ions from synthetic and industrial wastewater

“…Furthermore, the head group orientation of SC(NH₂)₂ allows multiple interactions with positive species within the bonding region. This is in contrast to one dimensional bonding behavior of CO(NH₂)₂, as also reported in other studies (Wilson and Tarbell, 1950;Stefaniu et al, 2015). This phenomenon favours sulphur-complexes-metal ions interactions compared to CO(NH₂)₂.…”

Examination of the structures, energetics, and vibrational frequencies of small sulfur‐containing prototypical dimers, (H2S)2 and H2O/H2S

“…The properties of molecules and reactions involving H 2 S and other sulfur-containing molecules have solicited few investigations since the 1970s. [7][8][9][10] Despite the prevalence and importance of these attractive SH interactions, particularly in biochemical systems containing cysteine residues [11][12][13][14][15][16] or other thiolcontaining biomolecules, [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] the homogeneous and heterogeneous S analogues of (H 2 O) 2 depicted in Figure 1 have received comparatively little attention. Investigations into the homogeneous (H 2 S) 2 and heterogeneous H 2 O/H 2 S dimers provide insight into interactions with sulfur-containing molecules as well as accurate energetics and vibrational signatures to compare with the H 2 O dimer.…”

Mechanically robust, readily repairable polymers via tailored noncovalent cross-linking

“…S10B). The thiourea group is special as an H-bonding motif (22), because UEG 3 , the urea analog of TUEG 3 , is semicrystalline ( Fig. 1, A and B, and fig.…”