Synthesis and micellar characterization of amphiphilic diblock copolymers based on poly(2-ethyl-2-oxazoline) and aliphatic polyesters

Sang Cheon Lee, Youngkyu Chang, Jin San Yoon, Chulhee Kim, Ick Chan Kwon, Yong Hee Kim, Seo Young Jeong

Research output: Contribution to journalArticle

200 Citations (Scopus)

Abstract

Amphiphilic diblock copolymers were synthesized based on poly(2-ethyl-2-oxazoline) (PEtOz) as a hydrophilic block and aliphatic polyesters such as poly(L-lactide) (PLA) or poly(ε-caprolactone) (PCL) as a hydrophobic block. Their micellar characteristics in an aqueous phase were investigated by using dynamic light scattering and fluorescence techniques. The block copolymers formed micelles in the aqueous phase with critical micelle concentrations (cmcs) in the range of 1.0-8.1 mg/L. The cmc values become lower upon increasing the length of the hydrophobic block. The mean diameter of the micelles were in the range of 108-192 nm, with a narrow distribution. In general, the micelle size increased as the hydrophobic PLA or PCL block became larger. The partition equilibrium constants, Kv, of pyrene in the micellar solutions of the block copolymers were from 1.79 × 105 to 5.88 × 105. For each block copolymer system of PEtOz-PLA or PEtOz-PCL, the Kv value increased as the length of the hydrophobic block increased. The steady-state fluorescence anisotropy values (r) of 1,6-diphenyl-1,3,5-hexatriene (DPH) were 0.265-0.284 in PEtOz-PLA solution and 0.189-0.196 in PEtOz-PCL solution. The anisotropy values of PEtOz-PLAs were higher than those of PEtOz-PCLs. The anisotropy values were independent of the length of the hydrophobic block when the chemical structures of the hydrophobic blocks were identical. The micelles underwent hydrogen bonding at pH <3.5 with poly(acrylic acid), which produced polymer complex precipitates that could be reversibly dispersed as micelles at pH >3.8.

Original languageEnglish
Pages (from-to)1847-1852
Number of pages6
JournalMacromolecules
Volume32
Issue number6
DOIs
Publication statusPublished - 1999 Mar 23
Externally publishedYes

Fingerprint

Polyesters
Micelles
Block copolymers
Anisotropy
Critical micelle concentration
Fluorescence
Pyrene
Equilibrium constants
Dynamic light scattering
Hydrogen bonds
Diphenylhexatriene
poly(2-ethyl-2-oxazoline)
polycaprolactone

ASJC Scopus subject areas

  • Materials Chemistry

Cite this

Synthesis and micellar characterization of amphiphilic diblock copolymers based on poly(2-ethyl-2-oxazoline) and aliphatic polyesters. / Lee, Sang Cheon; Chang, Youngkyu; Yoon, Jin San; Kim, Chulhee; Kwon, Ick Chan; Kim, Yong Hee; Jeong, Seo Young.

In: Macromolecules, Vol. 32, No. 6, 23.03.1999, p. 1847-1852.

Research output: Contribution to journalArticle

Lee, Sang Cheon ; Chang, Youngkyu ; Yoon, Jin San ; Kim, Chulhee ; Kwon, Ick Chan ; Kim, Yong Hee ; Jeong, Seo Young. / Synthesis and micellar characterization of amphiphilic diblock copolymers based on poly(2-ethyl-2-oxazoline) and aliphatic polyesters. In: Macromolecules. 1999 ; Vol. 32, No. 6. pp. 1847-1852.
@article{7fbbe4fcffb84e3da9ad7b67684036c3,
title = "Synthesis and micellar characterization of amphiphilic diblock copolymers based on poly(2-ethyl-2-oxazoline) and aliphatic polyesters",
abstract = "Amphiphilic diblock copolymers were synthesized based on poly(2-ethyl-2-oxazoline) (PEtOz) as a hydrophilic block and aliphatic polyesters such as poly(L-lactide) (PLA) or poly(ε-caprolactone) (PCL) as a hydrophobic block. Their micellar characteristics in an aqueous phase were investigated by using dynamic light scattering and fluorescence techniques. The block copolymers formed micelles in the aqueous phase with critical micelle concentrations (cmcs) in the range of 1.0-8.1 mg/L. The cmc values become lower upon increasing the length of the hydrophobic block. The mean diameter of the micelles were in the range of 108-192 nm, with a narrow distribution. In general, the micelle size increased as the hydrophobic PLA or PCL block became larger. The partition equilibrium constants, Kv, of pyrene in the micellar solutions of the block copolymers were from 1.79 × 105 to 5.88 × 105. For each block copolymer system of PEtOz-PLA or PEtOz-PCL, the Kv value increased as the length of the hydrophobic block increased. The steady-state fluorescence anisotropy values (r) of 1,6-diphenyl-1,3,5-hexatriene (DPH) were 0.265-0.284 in PEtOz-PLA solution and 0.189-0.196 in PEtOz-PCL solution. The anisotropy values of PEtOz-PLAs were higher than those of PEtOz-PCLs. The anisotropy values were independent of the length of the hydrophobic block when the chemical structures of the hydrophobic blocks were identical. The micelles underwent hydrogen bonding at pH <3.5 with poly(acrylic acid), which produced polymer complex precipitates that could be reversibly dispersed as micelles at pH >3.8.",
author = "Lee, {Sang Cheon} and Youngkyu Chang and Yoon, {Jin San} and Chulhee Kim and Kwon, {Ick Chan} and Kim, {Yong Hee} and Jeong, {Seo Young}",
year = "1999",
month = "3",
day = "23",
doi = "10.1021/ma981664k",
language = "English",
volume = "32",
pages = "1847--1852",
journal = "Macromolecules",
issn = "0024-9297",
publisher = "American Chemical Society",
number = "6",

}

TY - JOUR

T1 - Synthesis and micellar characterization of amphiphilic diblock copolymers based on poly(2-ethyl-2-oxazoline) and aliphatic polyesters

AU - Lee, Sang Cheon

AU - Chang, Youngkyu

AU - Yoon, Jin San

AU - Kim, Chulhee

AU - Kwon, Ick Chan

AU - Kim, Yong Hee

AU - Jeong, Seo Young

PY - 1999/3/23

Y1 - 1999/3/23

N2 - Amphiphilic diblock copolymers were synthesized based on poly(2-ethyl-2-oxazoline) (PEtOz) as a hydrophilic block and aliphatic polyesters such as poly(L-lactide) (PLA) or poly(ε-caprolactone) (PCL) as a hydrophobic block. Their micellar characteristics in an aqueous phase were investigated by using dynamic light scattering and fluorescence techniques. The block copolymers formed micelles in the aqueous phase with critical micelle concentrations (cmcs) in the range of 1.0-8.1 mg/L. The cmc values become lower upon increasing the length of the hydrophobic block. The mean diameter of the micelles were in the range of 108-192 nm, with a narrow distribution. In general, the micelle size increased as the hydrophobic PLA or PCL block became larger. The partition equilibrium constants, Kv, of pyrene in the micellar solutions of the block copolymers were from 1.79 × 105 to 5.88 × 105. For each block copolymer system of PEtOz-PLA or PEtOz-PCL, the Kv value increased as the length of the hydrophobic block increased. The steady-state fluorescence anisotropy values (r) of 1,6-diphenyl-1,3,5-hexatriene (DPH) were 0.265-0.284 in PEtOz-PLA solution and 0.189-0.196 in PEtOz-PCL solution. The anisotropy values of PEtOz-PLAs were higher than those of PEtOz-PCLs. The anisotropy values were independent of the length of the hydrophobic block when the chemical structures of the hydrophobic blocks were identical. The micelles underwent hydrogen bonding at pH <3.5 with poly(acrylic acid), which produced polymer complex precipitates that could be reversibly dispersed as micelles at pH >3.8.

AB - Amphiphilic diblock copolymers were synthesized based on poly(2-ethyl-2-oxazoline) (PEtOz) as a hydrophilic block and aliphatic polyesters such as poly(L-lactide) (PLA) or poly(ε-caprolactone) (PCL) as a hydrophobic block. Their micellar characteristics in an aqueous phase were investigated by using dynamic light scattering and fluorescence techniques. The block copolymers formed micelles in the aqueous phase with critical micelle concentrations (cmcs) in the range of 1.0-8.1 mg/L. The cmc values become lower upon increasing the length of the hydrophobic block. The mean diameter of the micelles were in the range of 108-192 nm, with a narrow distribution. In general, the micelle size increased as the hydrophobic PLA or PCL block became larger. The partition equilibrium constants, Kv, of pyrene in the micellar solutions of the block copolymers were from 1.79 × 105 to 5.88 × 105. For each block copolymer system of PEtOz-PLA or PEtOz-PCL, the Kv value increased as the length of the hydrophobic block increased. The steady-state fluorescence anisotropy values (r) of 1,6-diphenyl-1,3,5-hexatriene (DPH) were 0.265-0.284 in PEtOz-PLA solution and 0.189-0.196 in PEtOz-PCL solution. The anisotropy values of PEtOz-PLAs were higher than those of PEtOz-PCLs. The anisotropy values were independent of the length of the hydrophobic block when the chemical structures of the hydrophobic blocks were identical. The micelles underwent hydrogen bonding at pH <3.5 with poly(acrylic acid), which produced polymer complex precipitates that could be reversibly dispersed as micelles at pH >3.8.

UR - http://www.scopus.com/inward/record.url?scp=0032650468&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0032650468&partnerID=8YFLogxK

U2 - 10.1021/ma981664k

DO - 10.1021/ma981664k

M3 - Article

AN - SCOPUS:0032650468

VL - 32

SP - 1847

EP - 1852

JO - Macromolecules

JF - Macromolecules

SN - 0024-9297

IS - 6

ER -