Nanocomposites by Quantum Mechanics Thomas Prevenslik QED Radiations Discovery Bay, Hong Kong 1 Conference on Mechanics of Composites

Introduction 2 Conference on Mechanics of Composites Nanocomposites with uniform dispersion of NPs avoid agglomeration to significantly enhance mechanical properties. NPs = Nanoparticles. How can uniform dispersion of NPs be achieved? Fabricate large numbers of individual NPs enclosed in a shell of nanoscale thickness. Upon thermal processing in a 3D mold, the shells melt to form a composite with uniform NP spacing. NP Shell Mold

Enhanced Mechanical Properties Conference on Mechanics of Composites Charge uniform NP dispersion ? Coulomb Repulsion between NPs  Triaxial Stress State Enhanced Elastic Modulus But what if NP charges decay? 3

Electrets Conference on Mechanics of Composites Electrets are dielectric materials having a quasi- permanent electric charge High resistance of electrets allow charge claimed not to decay for a hundred years! Electrets are made from synthetic polymers Fluoropolymers Select PP having Young’s modulus = 20,000 psi PP = Polypropylene Metal NPs = Iron - Charge by ionization 4

Purpose MD simulations are presented to show significant stiffening by triaxial stress states using a nanoscale tensile specimen of PP including iron NPs on a spacing of 500 nm MD = molecular dynamics 5 Conference on Mechanics of Composites

Mechanism Mechanical properties are enhanced by QM QM = quantum mechanics. In classical physics, the NP atoms have heat capacity allowing atoms to increase in temperature during thermal processing, but not by QM By the Planck law, the NP atoms are precluded from having the heat capacity to increase in temperature. Instead, conservation of heat in thermal processing proceeds by QED inducing the NPs to create non-thermal EM radiation QED = quantum electrodynamics EM = electromagnetic. 6 Conference on Mechanics of Composites

QED induced EM radiation ionizes the metal NP removing electrons leaving a positive charge EM radiation at =200 nm  E = hc/  6.21 eV The EM radiation wavelength = 2 nd, where n and d are the refractive index and diameter of the NP. For metal NPs, n = 1.5  d = 200 nm / 3  70 nm Coulomb repulsion between the charged NPs  triaxial stress state that increases the Young’s modulus. Coulomb Repulsion 7 Conference on Mechanics of Composites

Theory Conference on Mechanics of Composites Heat Capacity of the Atom Conservation of Energy EM Confinement 8

Heat Capacity of the Atom 9 Conference on Mechanics of Composites Classical Physics (MD, Comsol) QM (kT = 0) kT eV Classical Physics (MD, Comsol) Nanoscale Macroscale 1950  Teller & Metropolis MD  PBC  valid for > 100  m Today, MD used in discrete nanostructures ! 1912  Debye’s phonons  h  = kT  valid for > 100  m Today, phonons used in nanostructures ! In NPs, the atom has no heat capacity by QM

Conference on Mechanics of Composites Conservation of Energy Without heat capacity, how do NPs conserve energy? Proposal Absorbed EM energy is conserved by creating QED radiation inside the NP - by frequency up - conversion to its EM resonance 10

NPs have high surface-to-volume ratios  All energy into surface  surface atoms under high EM confinement, but QM precludes temperature increase. QED converts the surface energy from thermal processing into standing EUV radiation hat ionizes the NP QED: EM energy into QM box  Create EM radiation at /2 = d QED  f = ( c/n) / / 2 = d E = h f EM Confinement 11 Conference on Mechanics of Composites Glove No Temperature Increase EUV Standing Wave electron +

MD Simulation Conference on Mechanics of Composites Simplification Model Analysis Results 12

Simplification Conference on Mechanics of Composites In the metal NP – PP composite, MD simulations usually consider all atoms The MD here differs - only metal NPs are simulated for simplicity as the PP continuum is insignificant 13

Model Conference on Mechanics of Composites. MD simulations of 500 nm spacing used a specimen having sides w = 2000 nm and length L = 10,000 nm comprising 500 NPs in a BCC configuration 14 w w F Support

 Lateral Constraint Conference on Mechanics of Composites    PP constrains NPs to move only in Z - direction 15

Results Conference on Mechanics of Composites 16

PP Results Conference on Mechanics of Composites 17 For a 500 nm NP spacing, the Young’s modulus of PP is enhanced 10 times. At nm, the enhancement is about 2 times

MD based on classical physics that assumes NP atoms have kT energy is invalid for nanocomposites MD based on QM requires heat during thermal processing to be conserved by QED inducing EM radiation that charges the metal NPs to produce Coulomb repulsion and a triaxial stress state to enhance the Young’s modulus of PP But, Whether the very large number of NPs can be economically produced is an open question ! Conclusions 18 Conference on Mechanics of Composites

Questions & Papers Conference on Mechanics of Composites