A comparative study of urea-induced aggregation of collapsed poly(n -isopropylacrylamide) and poly(N, N -diethylacrylamide) chains in aqueous solutions

Yijie Lu, Xiaodong Ye, Kejin Zhou, Wenjing Shi

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

The urea-induced aggregation of poly(N-isopropylacrylamide) (PNIPAM) and poly(N,N-diethylacrylamide) (PDEAM) globules was studied by using a combination of static and dynamic light scattering. Our results have revealed that urea acting as a cross-linker via formation of two hydrogen bonds with the amide groups of PNIPAM and PDEAM in different globules causes the aggregation, and the aggregation of PNIPAM and PDEAM globules is a reaction-limited cluster-cluster aggregation (RLCA) process. The aggregates have a uniform sphere structure that may be due to the restructuring of the aggregates. The aggregation rate of PNIPAM globules is slower than that of PDEAM, which might mainly contribute to the reasons that the amides groups of PNIPAM have more chance to be inside the globules because of the formation of intra- and inter-hydrogen bonds and the smaller number density of the PNIPAM aggregates at the original time. When the aqueous urea solutions were cooled and reheated to 40 C, the aggregation became faster than the first heating process, indicating that the urea molecules have replaced some water molecules binding to the amide groups at high temperature and some of the urea molecules remain interacting with the polymers even at the temperature lower than the cloud point temperature.

Original languageEnglish (US)
Pages (from-to)7481-7488
Number of pages8
JournalJournal of Physical Chemistry B
Volume117
Issue number24
DOIs
StatePublished - Jun 20 2013

Fingerprint

globules
ureas
Urea
Agglomeration
aqueous solutions
amides
Amides
Molecules
Hydrogen
hydrogen bonds
Hydrogen bonds
molecules
Temperature
Industrial heating
Dynamic light scattering
light scattering
poly-N-isopropylacrylamide
poly(N,N-diethylacrylamide)
heating
causes

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

Cite this

A comparative study of urea-induced aggregation of collapsed poly(n -isopropylacrylamide) and poly(N, N -diethylacrylamide) chains in aqueous solutions. / Lu, Yijie; Ye, Xiaodong; Zhou, Kejin; Shi, Wenjing.

In: Journal of Physical Chemistry B, Vol. 117, No. 24, 20.06.2013, p. 7481-7488.

Research output: Contribution to journalArticle

@article{e948f3940085427a8fba9642ce3054b6,
title = "A comparative study of urea-induced aggregation of collapsed poly(n -isopropylacrylamide) and poly(N, N -diethylacrylamide) chains in aqueous solutions",
abstract = "The urea-induced aggregation of poly(N-isopropylacrylamide) (PNIPAM) and poly(N,N-diethylacrylamide) (PDEAM) globules was studied by using a combination of static and dynamic light scattering. Our results have revealed that urea acting as a cross-linker via formation of two hydrogen bonds with the amide groups of PNIPAM and PDEAM in different globules causes the aggregation, and the aggregation of PNIPAM and PDEAM globules is a reaction-limited cluster-cluster aggregation (RLCA) process. The aggregates have a uniform sphere structure that may be due to the restructuring of the aggregates. The aggregation rate of PNIPAM globules is slower than that of PDEAM, which might mainly contribute to the reasons that the amides groups of PNIPAM have more chance to be inside the globules because of the formation of intra- and inter-hydrogen bonds and the smaller number density of the PNIPAM aggregates at the original time. When the aqueous urea solutions were cooled and reheated to 40 C, the aggregation became faster than the first heating process, indicating that the urea molecules have replaced some water molecules binding to the amide groups at high temperature and some of the urea molecules remain interacting with the polymers even at the temperature lower than the cloud point temperature.",
author = "Yijie Lu and Xiaodong Ye and Kejin Zhou and Wenjing Shi",
year = "2013",
month = "6",
day = "20",
doi = "10.1021/jp403555b",
language = "English (US)",
volume = "117",
pages = "7481--7488",
journal = "Journal of Physical Chemistry B Materials",
issn = "1520-6106",
publisher = "American Chemical Society",
number = "24",

}

TY - JOUR

T1 - A comparative study of urea-induced aggregation of collapsed poly(n -isopropylacrylamide) and poly(N, N -diethylacrylamide) chains in aqueous solutions

AU - Lu, Yijie

AU - Ye, Xiaodong

AU - Zhou, Kejin

AU - Shi, Wenjing

PY - 2013/6/20

Y1 - 2013/6/20

N2 - The urea-induced aggregation of poly(N-isopropylacrylamide) (PNIPAM) and poly(N,N-diethylacrylamide) (PDEAM) globules was studied by using a combination of static and dynamic light scattering. Our results have revealed that urea acting as a cross-linker via formation of two hydrogen bonds with the amide groups of PNIPAM and PDEAM in different globules causes the aggregation, and the aggregation of PNIPAM and PDEAM globules is a reaction-limited cluster-cluster aggregation (RLCA) process. The aggregates have a uniform sphere structure that may be due to the restructuring of the aggregates. The aggregation rate of PNIPAM globules is slower than that of PDEAM, which might mainly contribute to the reasons that the amides groups of PNIPAM have more chance to be inside the globules because of the formation of intra- and inter-hydrogen bonds and the smaller number density of the PNIPAM aggregates at the original time. When the aqueous urea solutions were cooled and reheated to 40 C, the aggregation became faster than the first heating process, indicating that the urea molecules have replaced some water molecules binding to the amide groups at high temperature and some of the urea molecules remain interacting with the polymers even at the temperature lower than the cloud point temperature.

AB - The urea-induced aggregation of poly(N-isopropylacrylamide) (PNIPAM) and poly(N,N-diethylacrylamide) (PDEAM) globules was studied by using a combination of static and dynamic light scattering. Our results have revealed that urea acting as a cross-linker via formation of two hydrogen bonds with the amide groups of PNIPAM and PDEAM in different globules causes the aggregation, and the aggregation of PNIPAM and PDEAM globules is a reaction-limited cluster-cluster aggregation (RLCA) process. The aggregates have a uniform sphere structure that may be due to the restructuring of the aggregates. The aggregation rate of PNIPAM globules is slower than that of PDEAM, which might mainly contribute to the reasons that the amides groups of PNIPAM have more chance to be inside the globules because of the formation of intra- and inter-hydrogen bonds and the smaller number density of the PNIPAM aggregates at the original time. When the aqueous urea solutions were cooled and reheated to 40 C, the aggregation became faster than the first heating process, indicating that the urea molecules have replaced some water molecules binding to the amide groups at high temperature and some of the urea molecules remain interacting with the polymers even at the temperature lower than the cloud point temperature.

UR - http://www.scopus.com/inward/record.url?scp=84879359727&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84879359727&partnerID=8YFLogxK

U2 - 10.1021/jp403555b

DO - 10.1021/jp403555b

M3 - Article

VL - 117

SP - 7481

EP - 7488

JO - Journal of Physical Chemistry B Materials

JF - Journal of Physical Chemistry B Materials

SN - 1520-6106

IS - 24

ER -