Role of Aromatic Interactions in Temperature-Sensitive Amphiphilic Supramolecular Assemblies

Abstract

Aromatic interactions were found to greatly influence the temperature-dependent dynamic behavior within supramolecular assemblies. Using an amphiphilic dendron, we systematically changed the hydrophobic groups introducing increasing levels of aromaticity while keeping the hydrophilic part constant. We show that the supramolecular assemblies become less sensitive to temperature changes when aromatic interactions in the aggregate are increased. Conversely, the absence of aromaticity in the hydrophobic moieties produces temperature-sensitive aggregates. These results show that subtle molecular-level interactions can be utilized to control temperature-sensitive behavior in the nanoscale. These findings open up new design strategies to rationally tune stimuli-responsive supramolecular assemblies on multiple spatiotemporal scales.

Molecular modelling of supramolecular polymers

“…Other types of external environmental stimuli (and their effect on supramolecular materials) that can be effectively explored by MD simulations are temperature [29,90,91], pH variations [92], etc. The group of Balasubramanian used AA-MD simulations demonstrating that the application of an external electric field can trigger the reorientation of the amide groups (dipoles) in a BTA fibre, provoking a switch in the helicity of the fibre (see Figure 6(b)) [93].…”

Toward Chemotactic Supramolecular Nanoparticles: From Autonomous Surface Motion Following Specific Chemical Gradients to Multivalency-Controlled Disassembly

“…This permits, for example, to graft onto their hydrophilic surface specific ligands (or chemical groups) that, exposed on the surface of the NP, allow the selective binding of determined receptors (or complementary chemical groups): changing the binding units and their number on the oligomer unit enables tuning of the Δ E bind . The use of such oligomers also permits modification of the hydrophobic groups, making the assembly more/less stable, changing the Δ E ass . Previous studies by our group demonstrated that molecular models can provide useful insights in such assemblies and in their stimuli-responsive behavior. − In detail, the self-assembling oligomers that we employ here as a reference platform (Figure a) are composed of a branched scaffold, three hydrophobic decyl chains (hydrophobic face), and three hydrophilic polyethylene glycol moieties (hydrophilic face).…”

Towards Chemotactic Supramolecular Nanoparticles: From Autonomous Surface Motion Following Specific Chemical Gradients to Multivalency-Controlled Disassembly

“…This allows, for example, to graft on their hydrophilic surface specific ligands (or chemical groups) that, exposed on the surface of the NP, allow to selectively bind determined receptors (or complementary chemical groups): changing the binding units and their number on the oligomer unit enables to tune the ΔEbind. The use of such oligomers also opens the opportunity to modify the hydrophobic groups, 36 making the assembly more/less stable, changing the ΔEass. Previous studies by our group demonstrated that molecular models can provide useful insight in such assemblies and in their stimuli-responsive behavior.…”

“…Previous studies by our group demonstrated that molecular models can provide useful insight in such assemblies and in their stimuli-responsive behavior. [36][37][38][39][40] In detail, the self-assembling oligomers that we employ here as a reference platform (Figure 3a) are composed of a branched scaffold, three hydrophobic decyl chains (hydrophobic face), and three hydrophilic polyethylene glycol moieties (hydrophilic face). Variable functionalities can be grafted onto the hydrophilic surface groups of these oligomers, which remain ex-posed on the NP surface upon oligomers self-assembly.…”

“…This has been recently done for similar selfassembling oligomers, showing remarkable effects on the temperature-responsive behavior of the NPs that these form. 36 As a further proof of concept, we thus studied the effect of changing the hydrophobic moieties in the oligomer units on the NP chemotaxis. Considering the reference oligomer of Figures 3-4 (named Original in Figure 6a), we systematically replaced its C10 hydrophobic units.…”