Preparation of Poly(N-isopropylacrylamide)-Monolayer-Protected Gold Clusters

Synthesis Methods, Core Size, and Thickness of Monolayer

Jun Shan, Markus Nuopponen, Hua Jiang, Esko Kauppinen, Heikki Tenhu (Corresponding Author)

Research output: Contribution to journalArticleScientificpeer-review

161 Citations (Scopus)

Abstract

The preparation of poly(N-isopropylacrylamide)-monolayer-protected clusters (PNIPAM-MPC) of gold nanoparticles was carried out in a homogeneous phase using three methods, in which three types of PNIPAM ligands were employed. The first type was comprised of PNIPAMs with narrow molar mass distributions, synthesized by reversible addition−fragmentation chain transfer (RAFT) polymerization and thus bearing a dithiobenzoate at the chain end. These polymers were used directly to passivate the gold nanoparticles upon the Schiffrin reaction in a one-pot synthesis. The second type of ligand was derived from the first one through hydrazinolysis, and they therefore contained a thiol end group. The third type of ligand was PNIPAMs obtained through conventional radical polymerization, postmodified to contain thiol end groups. The PNIPAM-MPCs were characterized by high-resolution transmission electron microscopy, UV−vis spectroscopy, and dynamic light scattering. The one-pot synthesis utilizing the ligands of the first type turned out to be a simple and facile method compared with the other two ways, with which the size of the gold nanoparticles can be easily manipulated mainly by adjusting the molar ratios of PNIPAM/HAuCl4. PNIPAM is a more efficient ligand to stabilize the gold nanoparticles in water and in organic solvents than alkanethiols. The surface density of PNIPAM chains ranged from 1.8 to 2.5 chain/nm2, which is much lower than that typical for alkanethiols. The thickness of a PNIPAM monolayer bound to the gold core is somewhat larger than the size of the random coil of the corresponding free PNIPAM in aqueous solution, which suggests that the conformation of a PNIPAM chain bound to the gold core is extended.
Original languageEnglish
Pages (from-to)4526-4533
Number of pages8
JournalMacromolecules
Volume36
Issue number12
DOIs
Publication statusPublished - 2003
MoE publication typeA1 Journal article-refereed

Fingerprint

Gold
Monolayers
Ligands
Nanoparticles
Bearings (structural)
Molar mass
Sulfhydryl Compounds
Dynamic light scattering
Free radical polymerization
High resolution transmission electron microscopy
Organic solvents
Conformations
poly-N-isopropylacrylamide
Polymerization
Spectroscopy
Polymers
Water

Keywords

  • gold
  • gold nanoparticles
  • nanoparticles
  • thiolated polymers
  • polymer ligands
  • stabilization
  • grafting

Cite this

Shan, Jun ; Nuopponen, Markus ; Jiang, Hua ; Kauppinen, Esko ; Tenhu, Heikki. / Preparation of Poly(N-isopropylacrylamide)-Monolayer-Protected Gold Clusters : Synthesis Methods, Core Size, and Thickness of Monolayer. In: Macromolecules. 2003 ; Vol. 36, No. 12. pp. 4526-4533.
@article{686d1af7ddec4b0c95a2bf0867682793,
title = "Preparation of Poly(N-isopropylacrylamide)-Monolayer-Protected Gold Clusters: Synthesis Methods, Core Size, and Thickness of Monolayer",
abstract = "The preparation of poly(N-isopropylacrylamide)-monolayer-protected clusters (PNIPAM-MPC) of gold nanoparticles was carried out in a homogeneous phase using three methods, in which three types of PNIPAM ligands were employed. The first type was comprised of PNIPAMs with narrow molar mass distributions, synthesized by reversible addition−fragmentation chain transfer (RAFT) polymerization and thus bearing a dithiobenzoate at the chain end. These polymers were used directly to passivate the gold nanoparticles upon the Schiffrin reaction in a one-pot synthesis. The second type of ligand was derived from the first one through hydrazinolysis, and they therefore contained a thiol end group. The third type of ligand was PNIPAMs obtained through conventional radical polymerization, postmodified to contain thiol end groups. The PNIPAM-MPCs were characterized by high-resolution transmission electron microscopy, UV−vis spectroscopy, and dynamic light scattering. The one-pot synthesis utilizing the ligands of the first type turned out to be a simple and facile method compared with the other two ways, with which the size of the gold nanoparticles can be easily manipulated mainly by adjusting the molar ratios of PNIPAM/HAuCl4. PNIPAM is a more efficient ligand to stabilize the gold nanoparticles in water and in organic solvents than alkanethiols. The surface density of PNIPAM chains ranged from 1.8 to 2.5 chain/nm2, which is much lower than that typical for alkanethiols. The thickness of a PNIPAM monolayer bound to the gold core is somewhat larger than the size of the random coil of the corresponding free PNIPAM in aqueous solution, which suggests that the conformation of a PNIPAM chain bound to the gold core is extended.",
keywords = "gold, gold nanoparticles, nanoparticles, thiolated polymers, polymer ligands, stabilization, grafting",
author = "Jun Shan and Markus Nuopponen and Hua Jiang and Esko Kauppinen and Heikki Tenhu",
year = "2003",
doi = "10.1021/ma034265k",
language = "English",
volume = "36",
pages = "4526--4533",
journal = "Macromolecules",
issn = "0024-9297",
publisher = "American Chemical Society",
number = "12",

}

Preparation of Poly(N-isopropylacrylamide)-Monolayer-Protected Gold Clusters : Synthesis Methods, Core Size, and Thickness of Monolayer. / Shan, Jun; Nuopponen, Markus; Jiang, Hua; Kauppinen, Esko; Tenhu, Heikki (Corresponding Author).

In: Macromolecules, Vol. 36, No. 12, 2003, p. 4526-4533.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Preparation of Poly(N-isopropylacrylamide)-Monolayer-Protected Gold Clusters

T2 - Synthesis Methods, Core Size, and Thickness of Monolayer

AU - Shan, Jun

AU - Nuopponen, Markus

AU - Jiang, Hua

AU - Kauppinen, Esko

AU - Tenhu, Heikki

PY - 2003

Y1 - 2003

N2 - The preparation of poly(N-isopropylacrylamide)-monolayer-protected clusters (PNIPAM-MPC) of gold nanoparticles was carried out in a homogeneous phase using three methods, in which three types of PNIPAM ligands were employed. The first type was comprised of PNIPAMs with narrow molar mass distributions, synthesized by reversible addition−fragmentation chain transfer (RAFT) polymerization and thus bearing a dithiobenzoate at the chain end. These polymers were used directly to passivate the gold nanoparticles upon the Schiffrin reaction in a one-pot synthesis. The second type of ligand was derived from the first one through hydrazinolysis, and they therefore contained a thiol end group. The third type of ligand was PNIPAMs obtained through conventional radical polymerization, postmodified to contain thiol end groups. The PNIPAM-MPCs were characterized by high-resolution transmission electron microscopy, UV−vis spectroscopy, and dynamic light scattering. The one-pot synthesis utilizing the ligands of the first type turned out to be a simple and facile method compared with the other two ways, with which the size of the gold nanoparticles can be easily manipulated mainly by adjusting the molar ratios of PNIPAM/HAuCl4. PNIPAM is a more efficient ligand to stabilize the gold nanoparticles in water and in organic solvents than alkanethiols. The surface density of PNIPAM chains ranged from 1.8 to 2.5 chain/nm2, which is much lower than that typical for alkanethiols. The thickness of a PNIPAM monolayer bound to the gold core is somewhat larger than the size of the random coil of the corresponding free PNIPAM in aqueous solution, which suggests that the conformation of a PNIPAM chain bound to the gold core is extended.

AB - The preparation of poly(N-isopropylacrylamide)-monolayer-protected clusters (PNIPAM-MPC) of gold nanoparticles was carried out in a homogeneous phase using three methods, in which three types of PNIPAM ligands were employed. The first type was comprised of PNIPAMs with narrow molar mass distributions, synthesized by reversible addition−fragmentation chain transfer (RAFT) polymerization and thus bearing a dithiobenzoate at the chain end. These polymers were used directly to passivate the gold nanoparticles upon the Schiffrin reaction in a one-pot synthesis. The second type of ligand was derived from the first one through hydrazinolysis, and they therefore contained a thiol end group. The third type of ligand was PNIPAMs obtained through conventional radical polymerization, postmodified to contain thiol end groups. The PNIPAM-MPCs were characterized by high-resolution transmission electron microscopy, UV−vis spectroscopy, and dynamic light scattering. The one-pot synthesis utilizing the ligands of the first type turned out to be a simple and facile method compared with the other two ways, with which the size of the gold nanoparticles can be easily manipulated mainly by adjusting the molar ratios of PNIPAM/HAuCl4. PNIPAM is a more efficient ligand to stabilize the gold nanoparticles in water and in organic solvents than alkanethiols. The surface density of PNIPAM chains ranged from 1.8 to 2.5 chain/nm2, which is much lower than that typical for alkanethiols. The thickness of a PNIPAM monolayer bound to the gold core is somewhat larger than the size of the random coil of the corresponding free PNIPAM in aqueous solution, which suggests that the conformation of a PNIPAM chain bound to the gold core is extended.

KW - gold

KW - gold nanoparticles

KW - nanoparticles

KW - thiolated polymers

KW - polymer ligands

KW - stabilization

KW - grafting

U2 - 10.1021/ma034265k

DO - 10.1021/ma034265k

M3 - Article

VL - 36

SP - 4526

EP - 4533

JO - Macromolecules

JF - Macromolecules

SN - 0024-9297

IS - 12

ER -