Abstract
This work presents a novel modeling approach to calculate the optical properties of gold nanoparticles coated with stimuli-responsive polymers. This approach combines, for the first time, a molecular description of the soft material with an electrodynamics calculation of the optical properties of the system. A mean-field molecular theory is first used to calculate the local density of the polymer and the position-dependent dielectric constant surrounding the nanoparticle. This information is then used to calculate the optical properties of the Au@polymer colloid by solving Maxwell's equations for an incident electromagnetic wave. Motivated by the interest in Au@PNIPAM and Au@PVP experimental systems, the theory is applied to study the effect of polymer collapse on the position of the localized surface plasmon resonance (LSPR) of the system. The most important results of the present study are as follows: (i) the LSPR always shifts to lower energies upon polymer collapse (in agreement with experimental results); this observation implies that the red shift expected due to increasing polymer density always overcomes the blue shift expected from decreasing layer thickness; (ii) the magnitude of the LSPR shift depends nonmonotonically on surface coverage and nanoparticle radius; and (iii) the formation of aggregates on the nanoparticle surface (due to microphase segregation) decreases the magnitude of the LSPR shift. These results highlight the importance of explicitly considering the coupling between the soft material and the inorganic components in determining the optical properties of the hybrid system.
| Original language | English |
|---|---|
| Pages (from-to) | 8397-8406 |
| Number of pages | 10 |
| Journal | ACS Nano |
| Volume | 6 |
| Issue number | 9 |
| DOIs | |
| Publication status | Published - Sep 25 2012 |
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Keywords
- discrete dipole approximation
- gold nanoparticle
- localized surface plasmon resonance
- LSPR sensing
- Mie theory
- molecular theory
- stimuli-responsive polymer
ASJC Scopus subject areas
- Engineering(all)
- Materials Science(all)
- Physics and Astronomy(all)
Cite this
Optical properties of responsive hybrid Au@polymer nanoparticles. / Tagliazucchi, Mario; Blaber, Martin G.; Schatz, George C; Weiss, Emily A; Szleifer, Igal.
In: ACS Nano, Vol. 6, No. 9, 25.09.2012, p. 8397-8406.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Optical properties of responsive hybrid Au@polymer nanoparticles
AU - Tagliazucchi, Mario
AU - Blaber, Martin G.
AU - Schatz, George C
AU - Weiss, Emily A
AU - Szleifer, Igal
PY - 2012/9/25
Y1 - 2012/9/25
N2 - This work presents a novel modeling approach to calculate the optical properties of gold nanoparticles coated with stimuli-responsive polymers. This approach combines, for the first time, a molecular description of the soft material with an electrodynamics calculation of the optical properties of the system. A mean-field molecular theory is first used to calculate the local density of the polymer and the position-dependent dielectric constant surrounding the nanoparticle. This information is then used to calculate the optical properties of the Au@polymer colloid by solving Maxwell's equations for an incident electromagnetic wave. Motivated by the interest in Au@PNIPAM and Au@PVP experimental systems, the theory is applied to study the effect of polymer collapse on the position of the localized surface plasmon resonance (LSPR) of the system. The most important results of the present study are as follows: (i) the LSPR always shifts to lower energies upon polymer collapse (in agreement with experimental results); this observation implies that the red shift expected due to increasing polymer density always overcomes the blue shift expected from decreasing layer thickness; (ii) the magnitude of the LSPR shift depends nonmonotonically on surface coverage and nanoparticle radius; and (iii) the formation of aggregates on the nanoparticle surface (due to microphase segregation) decreases the magnitude of the LSPR shift. These results highlight the importance of explicitly considering the coupling between the soft material and the inorganic components in determining the optical properties of the hybrid system.
AB - This work presents a novel modeling approach to calculate the optical properties of gold nanoparticles coated with stimuli-responsive polymers. This approach combines, for the first time, a molecular description of the soft material with an electrodynamics calculation of the optical properties of the system. A mean-field molecular theory is first used to calculate the local density of the polymer and the position-dependent dielectric constant surrounding the nanoparticle. This information is then used to calculate the optical properties of the Au@polymer colloid by solving Maxwell's equations for an incident electromagnetic wave. Motivated by the interest in Au@PNIPAM and Au@PVP experimental systems, the theory is applied to study the effect of polymer collapse on the position of the localized surface plasmon resonance (LSPR) of the system. The most important results of the present study are as follows: (i) the LSPR always shifts to lower energies upon polymer collapse (in agreement with experimental results); this observation implies that the red shift expected due to increasing polymer density always overcomes the blue shift expected from decreasing layer thickness; (ii) the magnitude of the LSPR shift depends nonmonotonically on surface coverage and nanoparticle radius; and (iii) the formation of aggregates on the nanoparticle surface (due to microphase segregation) decreases the magnitude of the LSPR shift. These results highlight the importance of explicitly considering the coupling between the soft material and the inorganic components in determining the optical properties of the hybrid system.
KW - discrete dipole approximation
KW - gold nanoparticle
KW - localized surface plasmon resonance
KW - LSPR sensing
KW - Mie theory
KW - molecular theory
KW - stimuli-responsive polymer
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U2 - 10.1021/nn303221y
DO - 10.1021/nn303221y
M3 - Article
VL - 6
SP - 8397
EP - 8406
JO - ACS Nano
JF - ACS Nano
SN - 1936-0851
IS - 9
ER -