Mechanical Behavior of Integrated Polymer Nanocomposites
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Mechanical Behavior of Integrated Polymer Nanocomposites. 65 wt%, Fe 2 O 3 /PU. SiC/PU. Co. THF. + Co +2. + KAuCl 4. 25 wt%, Fe 2 O 3 /VE. @10 K. V. V. Co. ASTM D412 Head Cross Speed: 15mm/min. Au. SiC-PU more strengthened. Functionalization effect: increased strength.

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Size 2 7 0 5 nm

Mechanical Behavior of Integrated Polymer Nanocomposites

65 wt%, Fe2O3/PU

SiC/PU

Co

THF

+Co+2

+ KAuCl4

25 wt%, Fe2O3/VE

@10 K

V

V

Co

  • ASTM D412

  • Head Cross Speed: 15mm/min

Au

  • SiC-PU more strengthened.

  • Functionalization effect: increased strength.

  • SIP method Fe2O3-PU: more flexible composite.

Magnetic Behavior of Integrated Polymer Nanocomposites

Fe2O3/VE

Fe2O3/PU

Fe/PU

Fe2O3/PPy

25 wt%

65 wt%

Hc=62 Oe

Hc=63 Oe

  • Matrix effect: a significant effect.

  • Particle loading;

  • Composite matrix materials.

  • Functionalization: little effect;

  • Materials become harder after dispersion into polymer matrix.

Hc=212 Oe

Microstructure of Integrated Polymer Nanocomposites

SEM Micrograph

TEM Micrograph (450 oC)

65 wt%, Fe2O3/PU

Fe2O3/VE

Fe/PU

as-rec.

SIP

DM

func.

  • Functionalization: good dispersion..

  • SIP favors particle dispersion.

  • Carbon-Fe composites.

Fe2O3 NPs

RT

7.3%

n=2

Fe/VE

Fe/PU

A

Nanoparticles

Electrode

Spin

V

CIP 5 um

Magnetic

Nonmagnetic

Matrix

H

RT

8.4%

  • At RT: GMR = 7.3 %

  • At 130 K, GMR=14.2%

  • At RT: GMR = 8.4%

  • Particle loading effect

Fe/PE

Particulate Magnetic Nanocomposites for Electronic Device Applications

Zhanhu Guo and H. Thomas Hahn

Multifunctional Composites Lab, Mechanical & Aerospace Engineering Department and Materials Science & Engineering Department

University of California Los Angeles, Los Angeles, CA 90095, USA

INTRODUCTION

Polymeric composites reinforced with inorganic fillers have attracted much interest due to their reduced weight, high homogeneity, cost-effective processability and tunable physical such as mechanical, magnetic, optical, electric and electronic properties. The applications have extended into the marine (Naval submarine) and airplane (Boeing 787) industries. Furthermore,

Particulate Co-Au Nanocomposite Application: GMR Sensor

  • Core-shell Fabrication

  • TEM micrograph

  • GMR Performance Test

  • Thermodynamic Analysis

  • Anodic reaction:

  • Co Co2++2e- ε0= - 0.277 V (1)

  • Cathodic reaction:

  • Au3++3e-Au ε0=1.401 V (2)

  • 3Co+2Au3+3Co2++2Au(3)

  • G3=3G1+2G2= - 10.068 F

Furthermore, nanoparticles (NPs) within the polymeric matrix render the nanocomposite potential electronic device applications such as fuel cells, photovoltaic (solar) cells, batteries and magnetic data storage. On the other side, the functional groups of the polymer surrounding the nanoparticles enable these polymer nanocomposites suitable for variable applications such as site-specific molecule targeting application in the biomedical areas.

  • Metallic conduction behavior

  • Possible due to small spacer distance

  • Size: 2.7 + 0.5 nm

Particle dispersion together with the interaction between fillers and polymer matrix are major challenges in the polymer composite manufacturing. The particle agglomerates and voids resulting from the poor bondage will serve as defect generating a deleterious physical properties such as lower tensile strength for structural material application and poorer electron transport path for integrated polymer composite electric/electronic device applications.

We have demonstrated strengthened polymer nanocomposite fabrication by surface engineering the particles. However, functionalization is an extra cost for production with high particle loading. We developed several simple and low-cost methods (surface-initiated-polymerization, monomer stabilization method, and solvent-extraction approach).

Polymer nanocomposites were developed into a granular giant magnetoresistance (GMR) sensor with the highest signal among these systems. Compared with metallic matrix GMR, the polymer matrix could be facile fabrication, low-cost usage without any packaging requirement and suitable for harsh environmental applications, ready to be used in specific biomedical areas.

Microwave absorber were built up from the polymer nanocomposites. The device shows weight reduction and fairly well performance.

GMR Sensor Application

Nanocomposite Fabrication Methodology

  • Composite Fabrication with Coupling Agent

  • Vinyl ester (VE) resin: matrix

Advantage of Polymer Nanocomposite Sensor

Chemical structure of (A) styrene (B) vinyl ester monomer

  • Easy fabrication

  • Light-weight

  • Stability

  • No need for extra package

  • Ready to be used in biomedical engineering

  • Iron oxide (Fe2O3) nanoparticles: 23 nm

Particulate Polymer Nanocomposite Application: Microwave Absorber

  • Methacryloxypropyltrimethoxysilane (MPS): coupling agent

Microwave absorber dimensions

outer diameter: 7.00 mm

inner diameter: 3.04 mm

  • Nanoparticle functionalization

Particulate Nanocomposite Application: GMR Sensor

Z: impedance; d: thickness

λ: wavelength in free space

MBRL: metal back reflection loss

  • GMR Operation Principle

  • GMR Sensor Evaluation

Fe/PU

Bold line: real

Thin line: imaginary

  • Condition: tetrahydrofuran and ultrasonication

  • Advantage: protecting NPs from dissolution; introduce C=C for covalent bondage

  • Disadvantage: still need organic solvent

anti-parallel: high R

parallel: low R

  • Surface-Initiated-Polymerization (SIP)

  • GMR Geometry and Measurement

catalyst + promoter + ultrasoincation nanoparticle activation

  • lower Permeability

  • Low magnetization

  • Higher Permitivity

  • Presence of oxide in Fe particles

  • Formation of particle-chain

  • Weight reduction of 38 % for discrete frequency at 10 GHz

  • Potential to save weight with improved metal NPs

  • Suitable for oxide nanoparticles

  • Advantage: no need for coupling agent

  • Conduction Mechanism

Concluding Remarks

  • Surface-initiated-polymerization approach to fabricate the polymer nanocomposite

  • Monomer stabilization method to manufacture the polymer nanocomposites

  • Unique magnetic property in the polymer nanocomposite system

  • Successful demonstration of GMR sensor fabricated from polymer nanocomposite

  • Polymer nanocomposite based microwave absorber with significant weight reduction

  • Monomer Stabilization Method (MSM)

  • GMR Calculation

Fe NPs

Monomer serves as a surfactant

VE

  • Related Publication

  • Z. Guo, et al., Journal of Materials Chemistry, 16, 2800-2808 (2006).

  • Z. Guo, et al., Journal of Materials Chemistry, 17, 806-813 (2007)

  • Z. Guo,. et al, Nanotechnology, 18, 335704 (2007)

  • Z. Guo, et al., Composites Science and Technology, 68, 164-170 (2008)

  • Z. Guo, et all, Electrochemical and Solid State Letters, 10(12) E31-E35 (2007)

  • Z. Guo, et al., Applied Physics Letter, 90, 053111 (2007)

  • Z. Guo, et al., Journal of Applied Physics, 10, 09M511 (2007)

  • Z. Guo, et al., Journal of the Electrochemical Society, 151 (1), D1-D5 (2005)

R(0) and R(H): resistance at zero and any applied field H.

  • Conduction Mechanism

Prospectus

  • Improve the sensitivity of GMR sensor

  • Fabricate GMR sensor prototype

  • Increase the microwave bandwidth

  • Conductive polymer based nanocomposite

PU

  • n=2, the conduction is hopping mechanism;

  • n=4, quasi three-dimensional variable range hopping.

  • Suitable for metal nanoparticles

  • Advantage: no need for coupling agent

  • Hopping/tunneling mechanism.


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