The Effect of Surface Functionalization of Graphene on the Electrical Conductivity of Epoxy-based Conductive Nanocomposites

Transcription

1 The Effect of Surface Functionalization of Graphene on the Electrical Conductivity of Epoxy-based Conductive Nanocomposites by Behnam Meschi Amoli, PhD Institute for Polymer Research, Waterloo Institute of Nanotechnology, Department of Chemical Engineering, University of Waterloo, Waterloo, ON, Canada May 6,

2 OUTLINE Introduction Hybrid Filler System using Graphene Ag NP-decoration SDS-stabilization Concluding remarks 2

3 Introduction 3

4 INTRODUCTION Interconnection Materials for Electronic Packaging Technologies Li et al., Science, 2005 Electrically Conductive Pathways Between Different Elements 4

5 INTRODUCTION Lead-based solders Lead-free materials Electrical Conductive Adhesives (ECAs) Polymeric Matrix Conductive Fillers Epoxy Micron-sized silver flakes 5

6 INTRODUCTION Commercial ECAs Advantages Environmental friendliness Mild processing conditions Low stress on substrate Fine pitch interconnect capability Disadvantages Poor mechanical strength Conductivity fatigue in harsh conditions (reliability) Low electrical conductivity Addition of more silver flakes Decreases the adhesive strength Increases the final cost Not effective after percolation threshold 6

7 INTRODUCTION Adding nano-sized fillers to the conventional formulation of ECAs to generate hybrid (micro-nano) filler system Objective: Improving the quality of interactions between conductive fillers to facilitate the electron transportation 7

8 INTRODUCTION Adding nano-sized fillers to the conventional formulation of ECAs to generate hybrid (micro-nano) filler system NP Spherical Ag NPs High aspect-ratio Ag NBs Graphene 8

9 Hybrid Filler System Using Graphene 9

10 GRAPHENE Flat monolayer of carbon atoms Densely packed into a 2D honeycomb lattice structure The thinnest and stiffest 2D nanostructure Extremely high aspect-ratio and electrical conductivity (1) COOH COOH Two functionalization OH COOH approaches Acid treatment (2) COOH OH COOH COOH COOH COOH HOOC COOH OH COOH OH OH OH Surface decoration with Ag NPs (4) OH MPA NaBH4 (3) COOH COOH COOH COOH OH Silver nitrate Surfactants (SDS) O S OH Ag NPs Ag nucleation sites Ag ions Covalent approach Non-covalent approach 10

11 Ag NP-DECORATED GRAPHENE o Surface decoration of graphene with Ag NPs functionalized with MPA Preparation of GO Initial nucleation Formation and functionalization of NPs B. Meschi Amoli et al., J. Mater. Sci: Mater Electron

12 AG NP-DECORATED GRAPHENE The Average Size 9.1 ± 3.1 nm B. Meschi Amoli et al., J. Mater. Sci: Mater Electron

13 AG NP-DECORATED GRAPHENE o Hybrid ECAs using the Ag NP-decorated graphene Hybrid ECAs have 1 wt% graphene Ω. cm Bulk resistivity of lead-based solders Ω. cm B. Meschi Amoli et al., J. Mater. Sci: Mater Electron

14 SDS-STABILIZED GRAPHENE o The stabilization of graphene using SDS Sonication B. Meschi Amoli et al., Carbon, accepted,

15 SDS-STABILIZED GRAPHENE o Hybrid ECAs using the SDS-stabilized graphene Small Gr 1µm Large Gr 5µm B. Meschi Amoli et al., Carbon, accepted, Ω. cm Compared to Ω. cm Ω. cm 15

16 Concluding remarks o Both functionalization approaches improved the electrical conductivity of ECAs o SDS-stabilization of graphene is more effective method for electrical conductivity improvement compared to Ag NPdecoration o A relatively low electrical resistivity of 35 Ω.cm was achieved using only 10 wt% silver flakes and 1.5 wt% SDS-stabilized graphene o A highly electrically conductive adhesive with the bulk resistivity less than that of lead-based solder was fabricated using 1.5 wt% SDS-stabilized graphene and 80 wt% silver flakes 16

17 LIST OF PUBLICATIONS Meschi Amoli et al., J. Mater. Chem., 2012, Gumfekar, Meschi Amoli et al., Poly. Sci. B: Poly. Phys., 2013, Meschi Amoli et al., Macromol. Mater. Eng., 2014, Meschi Amoli et al., J. Mater. Sci: Mater Electron., 2015, Meschi Amoli et al., Carbon, 2015, accepted. Meschi Amoli et al., J. Mater. Sci: Mater Electron., 2015, accepted. 17

18 AKNOWLEDGEMENTS Supervisors Professor Boxin Zhao Professor Norman Zhou 18

19 THANK YOU! 19

20 Backup Slides 20

21 Curing Mechanism of Epoxy 21

22 INTRODUCTION Electron conduction mechanism in an electrical network 22

23 MUA MPA AgNO3 HS(CH2)nCOOH Ag-MUA Ag-MPA B. Meschi Amoli et al., J. mater. chem.,

24 Ag NP-DECORATED GRAPHENE o Surface decoration of graphene with Ag NPs-functionalized with MPA Absorption (a.u.) Gr-Ag NPs Graphene GrO OH Wavenumber (cm ¹) B. Meschi Amoli et al., J. Mater. Sci: Mater Electron. 2015, , 24

25 Ag NP-DECORATED GRAPHENE o Initial nucleation B. Meschi Amoli et al., J. Mater. Sci: Mater Electron. 2015, , 25

26 Ag NP-DECORATED GRAPHENE o UV-vis & XRD B. Meschi Amoli et al., J. Mater. Sci: Mater Electron. 2015, , 26

27 AG NP-DECORATED GRAPHENE o Thermal behaviour of the decorated graphene 145 C B. Meschi Amoli et al., J. Mater. Sci: Mater Electron. 2015, , 27

28 AG NP-DECORATED GRAPHENE o Electrical Conductivity of Conductive fillers thin-films Temperature Increase B. Meschi Amoli et al., J. Mater. Sci: Mater Electron. 2015, , 28

29 SDS-STABILIZED GRAPHENE o The stabilization of graphene using SDS 0.38 nm XRD FTIR 0.30 nm Raman B. Meschi Amoli et al., Carbon, under revision,

30 SDS-stabilized Graphene C 0.85 Rev Cp (J/g) 0.8 T g : C C 0.7 Cp Tg Analysis Temperature ( C) Ethanol Content Name Description Control 1 (Neat Epoxy) Composition Control 2 (Ethanol Diluted) HCA-SGN HCA-SGS PHR 0 PHR 40.8 PHR 40.4 PHR 40.4 PHR wt% 0 wt% 26.5 wt% 12.5 wt% 12.5 wt% H tot J/g H norm J/g matrix T g C B. Meschi Amoli et al., Carbon, under revision,

31 SDS-STABILIZED GRAPHENE Ethanol Content Name Description Control 1 (Neat Epoxy) Composition Control 2 (Ethanol Diluted) HCA-SGN HCA-SGS PHR 0 PHR 40.8 PHR 40.4 PHR 40.4 PHR wt% 0 wt% 26.5 wt% 12.5 wt% 12.5 wt% H tot J/g H norm J/g matrix T g C B. Meschi Amoli et al., Carbon, under revision,

32 SDS-stabilized Graphene B. Meschi Amoli et al., Carbon, under revision,

33 SDS-stabilized Graphene o Thermal Stability B. Meschi Amoli et al., Carbon, under revision,

34 SDS-STABILIZED GRAPHENE o Hybrid ECAs using the SDS-stabilized graphene No Gr Small SDS-Gr Large SDS-Gr Large non modified Gr B. Meschi Amoli et al., Carbon, under revision,

35 Resistivity (Ω cm) 7.00E E E E E E E E E E E E E E00 Conventional ECA Non-modified small Gr non-modified large Gr AG NP decorated Gr SDS-Stabilized Gr (small) SDS Stabilized Gr (large) 35