"Soldier-Sergeant-Soldier" triblock copolymers: revealing the folded structure of single-chain polymeric nanoparticles.

Nobuhiko Hosono,E W Meijer,Anja R A Palmans

doi:10.1039/c4cc02789b

Abstract

"Soldiers-Sergeant-Soldiers" experiments performed on single-chain polymeric nanoparticles (SCPNs) with an ABA-type triblock architecture carrying chiral and achiral benzene-1,3,5-tricarboxamides (BTAs) in different blocks reveal that the BTAs form segregated, multiple stacks in a single SCPN.

Highlights

‘‘Soldiers–Sergeant–Soldiers’’ experiments performed on single-chain polymeric nanoparticles (SCPNs) with an ABA-type triblock architecture carrying chiral and achiral benzene-1,3,5-tricarboxamides (BTAs) in different blocks reveal that the BTAs form segregated, multiple stacks in a single SCPN
The folding behaviour of BTA-based SCPNs has been investigated extensively by our group for facile construction of nanometer-sized objects (Fig. 1a), with the ultimate aim to create artificial enzymatic systems.5b–d Since a better understanding of the folding process is crucial for tailoring the structure and functions of SCPNs, a quantitative estimation of the extent of folding was attempted by means of model analysis of temperature-dependent circular dichroism (CD) spectra.5d gathering direct experimental evidence on the internal folding structure still remains challenging since we are neither able to quantify the length of BTA stacks formed in SCPNs nor to distinguish between single and multi-domains present in the folded core
We concluded that the BTA moieties self-assemble into separate, individual stacks providing multiple, folded domains alongside the backbone polymer.5h In SCPNs designed for organic solvents, where the hydrophobic effect is absent, it remained unclear how BTA aggregation occurs and how it affects the global conformation of the polymers.5a Here we report intramolecular ‘‘Soldiers–Sergeant–Soldiers’’ (S–S–S) experiments using SCPNs with triblock architectures as a novel tool to elucidate the folding behavior of SCPNs in organic media

Summary

Introduction

‘‘Soldiers–Sergeant–Soldiers’’ experiments performed on single-chain polymeric nanoparticles (SCPNs) with an ABA-type triblock architecture carrying chiral and achiral benzene-1,3,5-tricarboxamides (BTAs) in different blocks reveal that the BTAs form segregated, multiple stacks in a single SCPN. In a SCPN the S–S–S experiment provides experimental evidence for the possibility of the chiral sergeant transferring its helical preference to the achiral soldiers.

Results

Conclusion