Supramolecular self-assembly of a polyelectrolyte chain based on step-growth polymerization of hydrophobic and hydrophilic monomers

Li Sun,Shang Ma,Jian Dong,Yongmei Chi,Chen Wang

doi:10.1039/c7ra09205a

Abstract

Polymerization of citric acid and hexamethylene diisocyanate and hydrolysis results in a polyelectrolyte PHMC. Noncovalent cross-linking of cooperative H-bonding units stabilizes the self-assembly of the PHMC chains into nanoparticles in water.

Highlights

Polymeric nanoparticles (NPs) with controlled morphologies are playing vital roles in materials separation, catalysis, targeted delivery of pharmaceuticals and biomedical imaging technology, where particles with a precise arrangement of chemical compositions and tailored morphology and size are required.[1,2,3,4] Amphiphilic block copolymers,[1,5,6,7,8,9,10] alternating, random, gra copolymers,[2,11,12,13,14,15,16,17,18,19,20,21,22,23] and homopolymers composed of both hydrophilic and hydrophobic components in repeating units,[24] are able to self-associate into various morphologies through an intra- or intermolecular fashion.Amphiphilic polyelectrolytes (APEs) consist of hydrophobic and ionizable monomer units.[11,12,15,16,25,26] While the strong hydrophobic attraction force may help the hydrophobic units to associate with each other in aqueous media, the electrostatic repulsion force among the ionizable units causes the latter to extend through the space as far as possible
FTIR and FT-Raman spectroscopic analysis of the polymer obtained from step 1 con rmed the formation of poly(hexamethylene citramide imide) (PHMCI)
To investigate the potential patterns of the hydrogen bonding in the nanoparticles cores, selected segments of the polycitramides were simulated using quantum chemical calculations and the results shown in Fig. 7 have con rmed the formation of the above cooperative H-bonding interactions

Summary

Introduction

Polymeric nanoparticles (NPs) with controlled morphologies are playing vital roles in materials separation, catalysis, targeted delivery of pharmaceuticals and biomedical imaging technology, where particles with a precise arrangement of chemical compositions and tailored morphology and size are required.[1,2,3,4] Amphiphilic block copolymers,[1,5,6,7,8,9,10] alternating, random, gra copolymers,[2,11,12,13,14,15,16,17,18,19,20,21,22,23] and homopolymers composed of both hydrophilic and hydrophobic components in repeating units,[24] are able to self-associate into various morphologies through an intra- or intermolecular fashion.Amphiphilic polyelectrolytes (APEs) consist of hydrophobic and ionizable monomer units.[11,12,15,16,25,26] While the strong hydrophobic attraction force may help the hydrophobic units to associate with each other in aqueous media, the electrostatic repulsion force among the ionizable units causes the latter to extend through the space as far as possible. Hydrolysis of PHMCI in alkaline solutions gives rise to poly(hexamethylene citramide) (PHMC) with a carboxylate side chain (see step 2 of Scheme 1).

Results

Conclusion