Nanoparticles of Block Ionomer Complexes from Double Hydrophilic Poly(acrylic acid)-b-poly(ethylene oxide)-b-poly(acrylic acid) Triblock Copolymer and Oppositely Charged Surfactant

Zhiping Peng,Xinxing Liu,Yuelong Sun,Zhen Tong

doi:10.1007/s11671-009-9448-x

Zhiping Peng, Xinxing Liu + Show 2 more

Open Access

https://doi.org/10.1007/s11671-009-9448-x

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Abstract

The novel water-dispersible nanoparticles from the double hydrophilic poly(acrylic acid)-b-poly(ethylene oxide)-b-poly(acrylic acid) (PAA-b-PEO-b-PAA) triblock copolymer and oppositely charged surfactant dodecyltrimethyl ammonium bromide (DTAB) were prepared by mixing the individual aqueous solutions. The structure of the nanoparticles was investigated as a function of the degree of neutralization (DN) by turbidimetry, dynamic light scattering (DSL),ζ-potential measurement, and atomic force microscope (AFM). The neutralization of the anionic PAA blocks with cationic DTAB accompanied with the hydrophobic interaction of alkyl tails of DTAB led to formation of core–shell nanoparticles with the core of the DTAB neutralized PAA blocks and the shell of the looped PEO blocks. The water-dispersible nanoparticles with negative ζ-potential were obtained over the DN range from 0.4 to 2.0 and their sizes depended on the DN. The looped PEO blocks hindered the further neutralization of the PAA blocks with cationic DTAB, resulting in existence of some negative charged PAA-b-PEO-b-PAA backbones even when DN > 1.0. The spherical and ellipsoidal nature of these nanoparticles was observed with AFM.

Highlights

The double hydrophilic block copolymers containing ionic and nonionic water-soluble blocks constitute a very active field in recent years for their unique aggregation behavior in aqueous solution [1, 2]
The results suggest that the PAA-b-PEO-b-PAA/dodecyltrimethyl ammonium bromide (DTAB) nanoparticles remain soluble and form stable aqueous dispersions even at the isoelectric point (DN = 1.0)
The novel water-dispersible nanoparticles of double hydrophilic PAA-b-PEO-b-PAA triblock copolymer binding with DTAB were prepared in aqueous solution at pH 9.0 as the result of the neutralization of anionic PAA blocks and cationic DTAB

Summary

Introduction

The double hydrophilic block copolymers containing ionic and nonionic water-soluble blocks (block ionomers) constitute a very active field in recent years for their unique aggregation behavior in aqueous solution [1, 2]. Abstract The novel water-dispersible nanoparticles from the double hydrophilic poly(acrylic acid)-b-poly(ethylene oxide)-b-poly(acrylic acid) (PAA-b-PEO-b-PAA) triblock copolymer and oppositely charged surfactant dodecyltrimethyl ammonium bromide (DTAB) were prepared by mixing the individual aqueous solutions.

Results

Conclusion