Theme 1.1: Electro-Mechanical Coupling in Soft Materials: Energy Scavenging and Storage

1. Theme 1.1: Electro-Mechanical Coupling in Soft Materials: Energy Scavenging and Storage ZoubeidaOunaies Penn State University Iimec2012-TAMU College Station, TX 1/18/02-1/19/02

2. Overview

4. Overview

5. Research Agenda Materials exhibiting electro-mechanical coupling,suchas piezoelectric and ferroelectric ceramics, electro-active polymers, and nano-composites for sensing, actuation, electrical energy harvesting, conversion and storage

6. One Approach…

7. Challenges Shortfalls of current electromechanical materials include: • small electromechanical coupling coefficients • high actuation voltage • Trade off between blocked stress, free strain and applied electric field • low mechanical to electrical energy conversion, resulting from dissipative dielectric losses • Low energy and work densities • Restricted operational temperatures and frequencies • Limited development of additional ‘functionality’

8. Can Nano Help Smart? • Introduce small amounts of Nanoparticles to achieve dramatic changes in • Mechanical, Thermal, Physical, Electrical and / or Chemical Properties • Introduce Multifunctionality (Structural + Electric; Structural + ElectroMechanical; Structural + Permeability; Structural + Biocompatibility) • Minimal change in density of the polymer At the same volume fraction (10 vol%). • Understand opportunities afforded by polymer nanocompositesto address current State-of-the-Art challenges in smart materials. Effect of particle shrinking from micrometric to nanometric size: interface increasingly dominates! interface particle Microcomposite Nanohybrid

9. Nanostructured/Nanoreinforced Polymers Nanostructured hybrids Nanofilled polymers -Introduce dramatic enhancement, new physical properties and novel behavior that are absent in unfilled matrices and particles  nanoscale effect! -Capitalize on inherent filler properties to enhance performance of composites Toughness Increase using Nanoclay(Shah et. al. 2004)

10. Overview

11. d Target Applications Light Flexible Piezoelectrics Nanocomposites Piezoelectric Ceramics and Ceramic-based Composites Smart Textiles Active fiber composites Wind Turbines Autonomous, unmanned, self-powered, and adaptive Power harnessing in ocean surges/waves along coastal regions

12. Overview

13. Exchange of students for periods of 4-6 months • EPT to TAMU • EPT to PSU • PSU to Morocco • Morocco to PSU • Faculty visits • EPT faculty to PSU • Competing for additional funding • Tunisia-Morocco cooperation for scientific research and technology • USA-Tunisia-Morocco State Department Grant • Fullbright • Tunisian ministry of higher education

14. Co-advising of PFE, MS and Ph.D. theses • Journal publications and conference proceedings • International conference organization • Non-profit professional society: NATEG

15. Overview

16. Development of Natural Fiber Composites Palm tree, Alfalfa and Agave Plant.

17. Development of natural fiber composites Palm tree, Alfalfa and Agave Plant.

18. New Composite Materials with Natural Reinforcement Applied Mechanics and Systems Research Laboratory TUNISIA POLYTECHNIC SCHOOL • Interest in integrating natural occuringfiber materials into composites • because of their functional and ecological qualities. • Tunisia possesses abundant sources of Alfalfa plants with promising physical and mechanical characteristics. Preparing Alfalfa short fibers specimens at PSU (varied lengths, random reinforcement) . • .Elaboration of a new composite material where the reinforcement consists of natural fibers extracted from Alfalfa plants: • identify the thermo-mechanicalproperties of naturalfiberseparately and in the composite material • conductbothnumerical and experimentalmeasurements • investigatedifferent arrangement of fibers (unidirectional, woven and randomwithvariedlengths

19. Collaborative Process…

20. Overview

21. Electric Field-Manipulation of Nanoreinforcements Flexibility and Transparency Cellulose • Abundantly available • Bio- compatible • Low cost • Bio-degradable • Easy to process Plants, Sea tunicates, Wood Actuation Mechanical reinforcement V. Favier et al 1995 Macromolecules

22. Synthesis and Extraction Acid Hydrolysis Multi-scale Processing and Characterization 300 V/mm, 30 min 10 Hz 25 kHz

23. Multifunctional Property Measurement and Analysis

24. Collaborative Process…

25. Overview

26. EPT-PSU Collaboration through Student and Faculty Exchange • -Student completed MS thesis, co-advised by Chafra,Najar, Ounaies • -Student conducting PhD research, co-advised by Chafra and Ounaies • -Faculty exchange leveraging the Fullbright program: Dr. MoezChafra from EPT to PSU. EPT students, EmnaHelal , conducting research at TAMU. experimental evidence of electrostriction by addition of small quantities of NPs.

27. Motivation: NanocompositeDielectrics. Commercially available polymers for capacitors: • Polypropylene: Energy density 1-1.2J/cc • Inexpensive • Easy to process Current requirements • Energy density (> 4 J/cc) • Low loss (<0.005) Monolithic materials: trade-off between e’ and Vb! Breakdown versus dielectric constant “Proposed universal relationship between dielectric breakdown and dielectric constant” J. McPherson et al. 2002. Texas Instruments, Silicon Technology Development.

28. Motivation: NanocompositeDielectrics. • To Store Large Amount of Electrical Energy at High Voltages for Long Periods of Time Without Significant Current Leakage. • Enable Lightweight, Compact, High-energy-density Capacitors • Optimize The Dielectric Permittivity And The Dielectric Breakdown Strength 2.3vol% NWTiO2@APS-PVDF With functionalization

29. Some Recent Results… Samples thickness ranging from 17mm to 24mm Enhancement > 500% with 4.6vol% F(NW)-PVDF

30. Breakdown Mechanisms • Possible mechanisms: • Intrinsic breakdown • Electronic breakdown • Thermal breakdown • Electromechanical breakdown Coulombic attractive forces Electrodes F Schematic representation of the relationship between the breakdown field Eb, the time to breakdown t, and the sample thickness d, Bluhm, 2006 [5] Spacer Sample

31. Breakdown mechanisms: Intrinsic? • Possible mechanisms: • Intrinsic breakdown • Electronic breakdown • Thermal breakdown • Electromechanical breakdown When the thickness increase, more defects are present in the sample  decrease in the dielectric breakdown The strongest dependence on thickness is for the composite with the highest particles content Ramp = 500V/s

32. Overview

33. Structural Health Monitoring of Polymer Matrix CompositesNon linear Ultrasonics Technique Objective: Development of a new Structural Health Monitoring methodology based on damage detection via non –linear wave modulation characteristics. Novel SHM System Experimental Setup for Impact Damage Detection in Composite Plates Results: Detection of Impact Damage Conclusions: • Ability to reveal even small damage sizes • Efficient for all common damage types of composites: • Delamination Debondings • Matrix cracks • Single lap adhesive joints Healthy 4J Impact load

34. Modeling of Delaminated Composite Beams with Active Piezoelectric Sensors Objectives: Development of new FE models with • Layerwise mechanics • Additional DOFs to simulate delamination • Coupled electromechanical system Conclusions: • Feasibility to reveal damage signatures • Ability to simulate delaminated system response • Agreement with experimental measurements

35. Break-out session 1

36. Afternoon break-out session: 3:15-5:00pm Room 1011B Moderated by P.Sharma and Z. Ounaies -Focus on electro-mechanical, mechanical reinforcement, opto-electric coupling, thermal management -Planning next year’s collaborations and activities

37. Technical Outcome Following Kick-off Meeting