Synthesis and 'schizophrenic' micellization of double hydrophilic AB 4 miktoarm star and AB diblock copolymers: Structure and kinetics of micellization

Zhishen Ge, Yuanli Cai, Jun Yin, Zhiyuan Zhu, Jingyi Rao, Shiyong Liu

Research output: Contribution to journalArticle

113 Citations (Scopus)

Abstract

Poly(N-isopropylacrylamide) (PNIPAM)-based tetrafunctional atom transfer radical polymerization (ATRP) macroinitiator (1b) was synthesized via addition reaction of mono-amino-terminated PNIPAM (1a) with glycidol, followed by esterification with excess 2-bromoisobutyryl bromide. Well-defined double hydrophilic miktoarm AB4 star copolymer, PNIPAM-b-(PDEA)4, was then synthesized by polymerizing 2-(diethylamino)ethyl methacrylate (DEA) via ATRP in 2-propanol at 45°C using 1b, where PDEA was poly(2- (diethylamino)ethyl methacrylate). For comparison, PNIPAM-b-PDEA linear diblock copolymer with comparable molecular weight and composition to that of PNIPAM-b-(PDEA)4 was prepared via reversible addition - fragmentation chain transfer (RAFT) polymerization. The pH- and thermoresponsive 'schizophrenic' micellization behavior of the obtained PNIPAM 65-b-(PDEA63)4 miktoarm star and PNIPAM 70-b-PDEA260 linear diblock copolymers were investigated by 1H NMR and laser light scattering (LLS). In acidic solution and elevated temperatures, PNIPAM-core micelles were formed; whereas at slightly alkaline conditions and room temperature, structurally inverted PDEA-core micelles were formed. The size of the PDEA-core micelles of PNIPAM 65-b-(PDEA63)4 is much smaller than that of PNIPAM70-b-PDEA260. Furthermore, the pH-induced micellization kinetics of the AB4 miktoarm star and AB block copolymers were investigated by the stopped-flow light scattering technique upon a pH jump from 4 to 10. Typical kinetic traces for the micellization of both types of copolymers can be well fitted with double-exponential functions, yielding a fast (τ1) and a slow (τ2) relaxation processes. τ1 for both copolymers decreased with increasing polymer concentration. τ2 was independent of polymer concentration for PNIPAM65-b-(PDEA63)4, whereas it decreased with increasing polymer concentration for PNIPAM 70-b-PDEA260. The chain architectural effects on the micellization properties and the underlying mechanisms were discussed in detail.

Original languageEnglish
Pages (from-to)1114-1122
Number of pages9
JournalLangmuir
Volume23
Issue number3
DOIs
Publication statusPublished - 2007 Jan 30
Externally publishedYes

Fingerprint

Micellization
Block copolymers
Stars
copolymers
Micelles
stars
Kinetics
Copolymers
Atom transfer radical polymerization
kinetics
synthesis
micelles
Light scattering
polymerization
Polymers
polymers
light scattering
Addition reactions
Polymerization
Exponential functions

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

Cite this

Synthesis and 'schizophrenic' micellization of double hydrophilic AB 4 miktoarm star and AB diblock copolymers : Structure and kinetics of micellization. / Ge, Zhishen; Cai, Yuanli; Yin, Jun; Zhu, Zhiyuan; Rao, Jingyi; Liu, Shiyong.

In: Langmuir, Vol. 23, No. 3, 30.01.2007, p. 1114-1122.

Research output: Contribution to journalArticle

@article{613c933ed0c74db6b676956ad3584633,
title = "Synthesis and 'schizophrenic' micellization of double hydrophilic AB 4 miktoarm star and AB diblock copolymers: Structure and kinetics of micellization",
abstract = "Poly(N-isopropylacrylamide) (PNIPAM)-based tetrafunctional atom transfer radical polymerization (ATRP) macroinitiator (1b) was synthesized via addition reaction of mono-amino-terminated PNIPAM (1a) with glycidol, followed by esterification with excess 2-bromoisobutyryl bromide. Well-defined double hydrophilic miktoarm AB4 star copolymer, PNIPAM-b-(PDEA)4, was then synthesized by polymerizing 2-(diethylamino)ethyl methacrylate (DEA) via ATRP in 2-propanol at 45°C using 1b, where PDEA was poly(2- (diethylamino)ethyl methacrylate). For comparison, PNIPAM-b-PDEA linear diblock copolymer with comparable molecular weight and composition to that of PNIPAM-b-(PDEA)4 was prepared via reversible addition - fragmentation chain transfer (RAFT) polymerization. The pH- and thermoresponsive 'schizophrenic' micellization behavior of the obtained PNIPAM 65-b-(PDEA63)4 miktoarm star and PNIPAM 70-b-PDEA260 linear diblock copolymers were investigated by 1H NMR and laser light scattering (LLS). In acidic solution and elevated temperatures, PNIPAM-core micelles were formed; whereas at slightly alkaline conditions and room temperature, structurally inverted PDEA-core micelles were formed. The size of the PDEA-core micelles of PNIPAM 65-b-(PDEA63)4 is much smaller than that of PNIPAM70-b-PDEA260. Furthermore, the pH-induced micellization kinetics of the AB4 miktoarm star and AB block copolymers were investigated by the stopped-flow light scattering technique upon a pH jump from 4 to 10. Typical kinetic traces for the micellization of both types of copolymers can be well fitted with double-exponential functions, yielding a fast (τ1) and a slow (τ2) relaxation processes. τ1 for both copolymers decreased with increasing polymer concentration. τ2 was independent of polymer concentration for PNIPAM65-b-(PDEA63)4, whereas it decreased with increasing polymer concentration for PNIPAM 70-b-PDEA260. The chain architectural effects on the micellization properties and the underlying mechanisms were discussed in detail.",
author = "Zhishen Ge and Yuanli Cai and Jun Yin and Zhiyuan Zhu and Jingyi Rao and Shiyong Liu",
year = "2007",
month = "1",
day = "30",
doi = "10.1021/la062719b",
language = "English",
volume = "23",
pages = "1114--1122",
journal = "Langmuir",
issn = "0743-7463",
publisher = "American Chemical Society",
number = "3",

}

TY - JOUR

T1 - Synthesis and 'schizophrenic' micellization of double hydrophilic AB 4 miktoarm star and AB diblock copolymers

T2 - Structure and kinetics of micellization

AU - Ge, Zhishen

AU - Cai, Yuanli

AU - Yin, Jun

AU - Zhu, Zhiyuan

AU - Rao, Jingyi

AU - Liu, Shiyong

PY - 2007/1/30

Y1 - 2007/1/30

N2 - Poly(N-isopropylacrylamide) (PNIPAM)-based tetrafunctional atom transfer radical polymerization (ATRP) macroinitiator (1b) was synthesized via addition reaction of mono-amino-terminated PNIPAM (1a) with glycidol, followed by esterification with excess 2-bromoisobutyryl bromide. Well-defined double hydrophilic miktoarm AB4 star copolymer, PNIPAM-b-(PDEA)4, was then synthesized by polymerizing 2-(diethylamino)ethyl methacrylate (DEA) via ATRP in 2-propanol at 45°C using 1b, where PDEA was poly(2- (diethylamino)ethyl methacrylate). For comparison, PNIPAM-b-PDEA linear diblock copolymer with comparable molecular weight and composition to that of PNIPAM-b-(PDEA)4 was prepared via reversible addition - fragmentation chain transfer (RAFT) polymerization. The pH- and thermoresponsive 'schizophrenic' micellization behavior of the obtained PNIPAM 65-b-(PDEA63)4 miktoarm star and PNIPAM 70-b-PDEA260 linear diblock copolymers were investigated by 1H NMR and laser light scattering (LLS). In acidic solution and elevated temperatures, PNIPAM-core micelles were formed; whereas at slightly alkaline conditions and room temperature, structurally inverted PDEA-core micelles were formed. The size of the PDEA-core micelles of PNIPAM 65-b-(PDEA63)4 is much smaller than that of PNIPAM70-b-PDEA260. Furthermore, the pH-induced micellization kinetics of the AB4 miktoarm star and AB block copolymers were investigated by the stopped-flow light scattering technique upon a pH jump from 4 to 10. Typical kinetic traces for the micellization of both types of copolymers can be well fitted with double-exponential functions, yielding a fast (τ1) and a slow (τ2) relaxation processes. τ1 for both copolymers decreased with increasing polymer concentration. τ2 was independent of polymer concentration for PNIPAM65-b-(PDEA63)4, whereas it decreased with increasing polymer concentration for PNIPAM 70-b-PDEA260. The chain architectural effects on the micellization properties and the underlying mechanisms were discussed in detail.

AB - Poly(N-isopropylacrylamide) (PNIPAM)-based tetrafunctional atom transfer radical polymerization (ATRP) macroinitiator (1b) was synthesized via addition reaction of mono-amino-terminated PNIPAM (1a) with glycidol, followed by esterification with excess 2-bromoisobutyryl bromide. Well-defined double hydrophilic miktoarm AB4 star copolymer, PNIPAM-b-(PDEA)4, was then synthesized by polymerizing 2-(diethylamino)ethyl methacrylate (DEA) via ATRP in 2-propanol at 45°C using 1b, where PDEA was poly(2- (diethylamino)ethyl methacrylate). For comparison, PNIPAM-b-PDEA linear diblock copolymer with comparable molecular weight and composition to that of PNIPAM-b-(PDEA)4 was prepared via reversible addition - fragmentation chain transfer (RAFT) polymerization. The pH- and thermoresponsive 'schizophrenic' micellization behavior of the obtained PNIPAM 65-b-(PDEA63)4 miktoarm star and PNIPAM 70-b-PDEA260 linear diblock copolymers were investigated by 1H NMR and laser light scattering (LLS). In acidic solution and elevated temperatures, PNIPAM-core micelles were formed; whereas at slightly alkaline conditions and room temperature, structurally inverted PDEA-core micelles were formed. The size of the PDEA-core micelles of PNIPAM 65-b-(PDEA63)4 is much smaller than that of PNIPAM70-b-PDEA260. Furthermore, the pH-induced micellization kinetics of the AB4 miktoarm star and AB block copolymers were investigated by the stopped-flow light scattering technique upon a pH jump from 4 to 10. Typical kinetic traces for the micellization of both types of copolymers can be well fitted with double-exponential functions, yielding a fast (τ1) and a slow (τ2) relaxation processes. τ1 for both copolymers decreased with increasing polymer concentration. τ2 was independent of polymer concentration for PNIPAM65-b-(PDEA63)4, whereas it decreased with increasing polymer concentration for PNIPAM 70-b-PDEA260. The chain architectural effects on the micellization properties and the underlying mechanisms were discussed in detail.

UR - http://www.scopus.com/inward/record.url?scp=33847234592&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33847234592&partnerID=8YFLogxK

U2 - 10.1021/la062719b

DO - 10.1021/la062719b

M3 - Article

C2 - 17241021

AN - SCOPUS:33847234592

VL - 23

SP - 1114

EP - 1122

JO - Langmuir

JF - Langmuir

SN - 0743-7463

IS - 3

ER -