Effect of Nanoparticle Architecture on 

Mechanical Properties of Polymer 

Composites

Madeleine Pasco
What is a nanocomposite polymer?

nm
What is a nanocomposite polymer?
What is a nanocomposite polymer?
Engine coating

[1] [2]

Biological uses

Nanoparticles and nanoparticle-polymer composites have a wide variety of uses and 

come in a range of shapes and sizes.

Deep-penetrating skin cream

[3]

Tennis balls

[3]

[1] M. Bruchez, M. Moronne, P. Gin, S. Weiss, A. Alivisatos. (1998). “Semiconductor Nanocrystals as Fluorescent Biological Labels.” Science. [2] B.

Coxworth. (2014). “Nanoparticle coating could let aircraft engines last three times longer.” Gizmag. [3] R. Paul. (2003). “The Top Ten Nanotech

Products of 2003.” Forbes.

Certain commercial equipment, instruments, or materials are identified in this paper to foster understanding. Such identification does not imply

recommendation or endorsement by the National Institute of Standards and Technology, nor does it imply that the materials or equipment

identified are necessarily the best available for the purpose.
Nanoparticles come in a variety of sizes and shapes. We focused on spherical 

morphologies. 

Linear PMMA

100 kg/mol

Silica

13 nm diameter

PEO

200 kg/mol

Star PMMA

312 kg/mol
0.500 g

Samples are prepared to get an even distribution of nanoparticle in polymer.
[4]

Neutrons interact with the nuclei of atoms and so are able to detect lighter atoms 

than can X-rays, as well as detect differences between isotopes. 

[5]

[4] National Institute of Standards and Technology. (2015). “The SANS

Toolbox.” NIST Center for Neutron Research. [5] R. Pynn. “Neutron

Scattering: A Primer.” Los Alamos Neutron Science Center.
Sample

2D Neutron Detector

Small-angle neutron scattering (SANS) was used to measure size and distribution of 

particles in the samples.
National Institute of Standards and Technology. (2015). “The SANS Toolbox.” NIST Center for Neutron Research.

Small-angle neutron scattering (SANS) was used to measure size and distribution of 

particles in the samples.
The vector difference between the incident beam and the scatter beam is called “Q”. 

Isotropic scattering allows us to take a circular average of intensity as a function of Q. 

Θ

Q

Q (1/Å)

Intensity (1/cm)

National Institute of Standards and Technology. (2015). “The SANS Toolbox.” NIST Center for Neutron Research.

1.00E+00

1.00E+01

1.00E+02

1.00E+03

0.001 0.01 0.1 1
Stitching together data across Q-ranges reveals the behavior of the samples over a 

large length scale. 

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

1.00E+06

0.001 0.01 0.1 1

Intensity (1/cm)

Q (1/Å)

Low Q (15.3 m)

Mid Q (13 m)

High Q (4 m)

Highest Q (1 m)
Star radius can be calculated from the linear radius of gyration

Particle Molecular Weight Calculated Radius

13 nm Silica 6.5 nm

55 nm Silica 27.5 nm

Linear PMMA 100 kg/mol 8.06 nm

Star PMMA 312 kg/mol 6.17 nm

R0

2/M from James E. Mark, “Polymer Solution Thermodynamics.” Massachusetts Institute of Technology. 

Rg

Rg,linear =

R0

2

M ∗ M

6

∗

1

10
1.00E-02

1.00E-01

1.00E+00

0.001 0.01 0.1 1

Intensity (1/cm)

Q (1/Å)

First we measured dilute solutions of nanoparticles without polymer.

1.00E-01

1.00E+00

1.00E+01

1.00E+02

1.00E+03

0.001 0.01 0.1 1

Intensity (1/cm)

Q (1/Å)

Star PMMA

Star form factor fit 

Linear PMMA

Debye fit

13 nm silica

Sphere shape factor fit 

55 nm silica

Sphere shape factor fit
Comparison of theoretical size, size alone, and size in polymer.

Particle Molecular Weight Theoretical Radius Radius in Solution

13 nm Silica - 6.5 nm 7.2 ± 0.03 nm

55 nm Silica - 27.5 nm 24.6 ± 0.07nm

Linear PMMA 100 kg/mol 8.06 nm 7.9 ± 0.05 nm

Star PMMA 312 kg/mol 6.17 nm 9.6 ± 1.1 nm
At 1% 13nm silica, the data shows the particles are spherical.

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

0.001 0.1

I(Q) (1/cm)

1%
1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

0.001 0.1

I(Q) (1/cm)

1%

0.001 0.01 0.1 1

Q (1/A)

5%

Q*

d ≈

2π

Q∗

As silica concentration increases, a peak forms showing a uniform dispersal of particles 

in the polymer. 
As silica concentration increases, a peak forms showing a uniform dispersal of particles 

in the polymer. 

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

0.001 0.1

I(Q) (1/cm)

1%

0.001 0.01 0.1 1

Q (1/A)

5%

0.001 0.01 0.1 1

10%

d=30.36 nm

d=24.09 nm
0.001 0.01 0.1 1

Q (1/A)

5%

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

0.001 0.01 0.1 1

I(Q) (1/cm)

1%

0.001 0.01 0.1 1

10%

The 13 nm silica is more evenly dispersed in 20 kg/mol PEO than in 200 kg/mol PEO.

PEO 20 kg/mol

PEO 200 kg/mol
1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

0.001 0.1

Intensity (1/cm)

1%

0.001 0.01 0.1 1

Q (1/Å)

5%

0.001 0.01 0.1 1

10%

13 nm silica

55 nm silica

55 nm silica is not as well-dispersed as 13 nm silica at 5% concentration, but shows 

more uniform interface distance at 10%.
Linear and star PMMA did not differ greatly in dispersion or size over varying 

concentrations.

1.00E-02

1.00E-01

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

0.001 0.01 0.1 1

I(Q) (1/cm)

Q (1/Å)

10% linear

PMMA

5% linear

PMMA

1% linear

PMMA

0.001 0.01 0.1 1

Q (1/Å)

10% star

PMMA

5% star

PMMA

1% star

PMMA
Strain applied (rotates)

γ = γ0 sin(ωt)

Stress measured (stationary)

σ = σ 0 sin(ωt + δ)

Transducer

Motor

Sample

G′=

σ0

γ0

cos(δ)

Storage (Elastic) Modulus

GG′′=

σ0

γ0

sin(δ)

Loss (Viscous) Modulus

Rheology is the study of how a material flows. 
1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

1.00E+06

0.01 0.1 1 10 100 1000

Angular Frequency (rad/s)

(3%) Storage Modulus

(3%) Loss Modulus

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

1.00E+06

0.01 0.1 1 10 100 1000

(10%) Storage Modulus

(10%) Loss Modulus

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

1.00E+06

0.01 0.1 1 10 100 1000

Storage and Loss Moduli (Pa)

Angular Frequency (rad/s)

(5%) Storage Modulus

(5%) Loss Modulus

13 nm silica composite becomes more solid-like as nanoparticle concentration increases.

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

1.00E+06

0.01 0.1 1 10 100 1000

(1%) Storage Modulus

(1%) Loss Modulus

PEO (200 kg/mol) Storage Modulus

PEO (200 kg/mol)
1.00E-01

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

1.00E+06

0.01 0.1 1 10 100 1000

10% Storage Modulus

10% Loss Modulus

1.00E-01

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

1.00E+06

0.01 0.1 1 10 100 1000

Storage and Loss Moduli (Pa)

Angular Frequency (rad/s)

5% Storage Modulus

5% Loss Modulus

1.00E-01

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

1.00E+06

0.01 0.1 1 10 100 1000

3% Storage Modulus

3% Loss Modulus

Star PMMA composite becomes more solid-like as nanoparticle concentration increases.

1.00E-01

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

1.00E+06

0.01 0.1 1 10 100 1000

1% Storage Modulus

1% Loss Modulus

PEO (200 kg/mol) storage modulus

PEO (200 kg/mol) Loss Modulus
1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

0.01 0.1 1 10 100 1000

Storage and Loss Moduli (Pa)

Angular Frequency (rad/s)

5% Storage Modulus

5% Loss Modulus

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

0.01 0.1 1 10 100 1000

3% Storage Modulus

3% Loss Modulus

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

0.01 0.1 1 10 100 1000

10% Storage Modulus

10% Loss Modulus

Linear PMMA does not become significantly more solid-like with increasing concentration.

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

0.01 0.1 1 10 100 1000

1% Storage Modulus

1% Loss Modulus

PEO (200 kg/mol) Storage Modulus

PEO (200 kg/mol) Loss Modulus
1

10

100

1000

10000

100000

1000000

0 5 10 15 20

Complex Viscosity (Pa-s) at 0.1 rad/s

Amount Nanoparticle (%)

Linear PMMA (100 kg/mol)

Star PMMA (312 kg/mol)

Silica 13nm

Just PEO (200 kg/mol)

Complex viscosity (η∗) of composite increases with increasing concentration of nanoparticle.

η∗=

GG′2 + GG′′2

ω
Composite rigidity increased with particle concentration and compactness. 

Rigidity Imparted
Thank you!

Erkan Senses

Antonio Faraone

Michihiro Nagao

Javen Weston

NIST Center for Neutron Research

National Institute of Standards and Technology

National Science Foundation, Center for High Resolution Neutron Scattering