# Presentation: 428416

## Nanotechnology Applications for Green Manufacturing

- Lawrence T. Drzal
- Dept of Chemical Engineering and Materials Science
- Composite Materials and Strctures Center
- Michigan State University

## Manufacturing (def.)

**The conversion of materials and energy into useful products through a designed process utilizing a combination of chemical, biological and mechanical processes...**
**...****(green manufacturing) at the same time reducing waste, minimizing pollution, protecting human health and the environment.**
**Nanotechnology can enable the transition.**

## Nanotechnology Elements

**Morphologies**
**Nanoparticles (amorphous or crystalline)**
**Nanotubes**
**Nanoplatelets**
**Nanolayers (monolayers)**
**Physical and Chemical Properties**
**Small number of atoms**
**High surface area**
**Surface activity and reactivity**
**Size dependent optical, electronic and chemical properties**
**Self-Assemble**
**Respond to electrostatic, hydrogen bond, polar, hydrophilic, hydrophobic forces**

## Manufacturing 

**Manufacturing **
**Operations**
**Impacted by **
**Nanotechnology**

## e.g. Microelectronics 

**Currently a ‘top-down’ lithographic approach**
**Large amounts of hazardous materials and resources**
**Part Integration and toxic components prevent recycling**
**32 MB microchip**
**Requires 1.7kg of fossil fuel and 32 kg of water***
**‘****Bottom-up’ nanotechnology approaches can  replace current chip production methods**
**Lithography**
**Nanoparticle**
**Self-assembly**

**Environ.Sci.Tech.,*_*36*_*, 55-4-5510 (2004)*

## Nonvolatile Computer Memory Through Self Assembly

**Cobalt nanoparticles form rings from nanoparticles which link up and self-assemble into rings.**
**The magnetic dipoles responsible for nanoring formation also produce a collective magnetic flux within the rings themselves, stemming from the magnetic poles each particle possesses. But after the particles form rings, the net magnetic effect is zero outside. The researchers developed conditions leading to the self-assembly of the cobalt nanorings and were able to observe directly the flux-closure states, which are stable at room temperature. **
**---*****Wei , Tripp and Dunin-Borkowski (Purdue-Cambridge) November 2003 Angewandte Chemie. ***

## Epitaxial self-assembly of block copolymers on lithographically defined nanopatterned substrates

**Manufacturing microelectronics through manipulating block copolymers to form into desirable patterns – e.g. parallel lines. **
**Lithography used to create patterns in the surface chemistry of a polymer.**
**The block copolymers on the surface arranged themselves into the underlying pattern without imperfections. **
***---Neeley, dePablo and Stoykovich, Nature, July 24, 2003***

## Self-assembled 3D Designer Material

**Precision chemistry methods developed to alter nanoparticles sizes in increments of less than one nanometer and varying in size by less than 5%**
**Tailor the experimental conditions so the particles would self-assemble themselves into repeating 3-D crystal strctures. **
**To produce multiconstituent structures **
**iron oxide particles 11 nanometers in diameter**
**lead selenide particles 6 nanometers in diameter**
**~60,000 atoms in one of the iron oxide nanoparticles and ~3,000 atoms in the lead selenide particles.**
**--*****-Redl, Cho et al., Nature, June 26, 2004 (Columbia, IBM and U NewOrleans)***

## Enzyme "Ink" For Nanomanufacturing 

**An enzyme ‘DNase I’ was the ‘ink’ in a process called dip-pen nanolithography -- a technique for etching or writing at the nanoscale level. **
**The dip-pen allowed them to inscribe precise stripes of DNase I ink on a gold plate, which they had previously coated with a thick forest of short DNA strands. The stripes of the enzyme were 100 nanometers wide**
**The enzyme was activated with a magnesium-containing solution to allow it to efficiently breaks down DNA in its path. **
**The stripes of activated enzyme carved out 400 nm-wide "troughs" in the DNA coating.  **
***---Chilkoti, J. Amer. Chem. Soc., May 2004, (Duke U) ***

## e.g. Structural Polymer Composites 

**Currently utilizes petroleum based materials**
**Energy intensive processing methods**
**Significant VOCs**
**Large amounts of hazardous materials and resources for fabrication and surface preparation**
**Limited recycle, reuse capacity**
**Biobased polymers have less than useful mechanical properties that can be improved by the addition of nanoparticles (nanoreinforcements)**
**Nanoreinforcements can add multifunctionality to polymers through small additions of these nanoparticles.**

**Environ.Sci.Tech.,*_*36*_*, 55-4-5510 (2004)*

## Fiber Reinforced Plastic Composites 

***(Plast. News Aug. 2003)***

***Fiber Reinforced Plastic Composites ***
***Usage in 2003 - 2.5 x 10******9****** lb***

**Glass used in 95% of cases to reinforce thermoplastics/thermosetting composite**

## Potential Polymer and Composite Property Modifications resulting from Use of Nanoreinforcements

**Mechanical-Structural **
**High Stiffness, High Strength, Toughness, Low Density **
**Electrical **
**Conductor, Semi-conductor, Insulator**
**ES charge dissipation, ES painting, EMI shielding, sensors, smart materials, antenna**
**Thermal**
**Conductor, Insulator**
**CTE, Thermal Conductivity**
**Barrier **
**Chemical, Biological, Flammability**

## Nanoreinforcement Multifunctionality 

|  | Exfoliated 
Clay | Carbon Nanotube
VGCF | Exfoliated h-BN
BN Nanotubes | Cellulose Nanowhisker | Graphite
NanoPlatelets |
| --- | --- | --- | --- | --- | --- |
| PHYSICAL 
STRUCTURE | Platelet
~1nm x 100nm | Cylinder
NT  ~1nm X 100nm
VGCF  ~20nm X 100um | Layer | Needle-Whisker | Platelet
~1nm X 100nm |
| CHEMICAL 
STRUCTURE | SiO2, Al2O3, MgO, 
K2O, Fe2O3 | Graphene
(chair, zigzag, chiral) | Boron Nitride | Cellulose | Graphene |
| INTERACTIONS  | Hydrogen bond
Dipole-Dipole  |  π - π | Hydrogen bond | Hydrogen Bond | π - π
 |
| TENSILE 
MODULUS | 0.17 TPa | NT    1.0-1.7 TPa
VGCF   0.25-0.5 TPa | ~1 TPa | ~ 130 GPa | ~1.0 TPa |
| TENSILE 
STRENGTH | ~1 GPa | (NT  180 GPa)
VGCF  3-7 GPa | ? | 10 GPa | ~(10-20 GPa) |
| ELECTRICAL
RESISTIVITY | 1010 – 1016 Ω cm |  NT    ~ 50 x 10-6 Ω cm
VGCF  5-100 x 10-3 Ω cm | insulator | 1010 – 1016 Ω cm | ~ 50 x 10-6 Ω cm║
~ 1 Ω cm┴ |
| THERMAL CONDUCTIVITY | 6.7 x 10-1 W/m K | 3000 W/m K (NT)
20-2000 W/m K (VGCF) | conductor | insulator | 3000 W/m K) ║
6 W/m K ┴ |
| COEF. 
THERMAL EXP. | 8 – 16 x 10-6 | -1 x 10-6 | ~1 x 10-6
 | 8 – 16 x 10-6 | -1 x 10-6 ║
29 x 10-6 ┴ |
| DENSITY | 2.8 – 3.0 g/cm3 |   NT     1.2 – 1.4 g/cm3
VGCF  1.8-2.1 g/cm3 | ~2.0 g/cm3 | 1.2 g/cm3 | ~2.0 g/cm3 |

## Clay and Organically Modified NanoClay

**Solvated counter-**
**ions: Na****+,**** Li****+****, Ca****2+**

- Na+

- N+

- N+

- N+

- N+

- N+

- N+

- N+

- N+

- Na+

- Na+

- Na+

- Na+

- Na+

- Na+

- Na+

- Na+

- Na+

- Na+

**Na****+****-Montmorillonite**

**Modified organophilic clay**

- Na+

- Na+

- Na+

- Na+

- Na+

- Na+

- Na+

- Na+

- Na+

- Na+

- Na+

- Na+

- N+

- N+

- N+

- N+

- N+

- N+

**+**

**Clay and Organically Modified NanoClay**

**~2nm**

**Modification by 4****0**** ammonium**

**Octahedra AlO****6**

**Tetrahedra SiO****4**

**Tetrahedra SiO****4**

**d-spacing**

**Organic modifier**

## Nanoclay Improves Properties of PHB to be competitive with TPO

**Addition on nanoclay improves the impact strength by 440% (even more than TPO)**

**The modulus of PHB modified (~TPO) by addition of nanoclay**

***Nanoclay Improves Properties of PHB to be competitive with TPO***

**Notes:**
These inherently brittle bacterial bioplastic Polyhydroxybutyrate (PHB) was successfully toughened. The effects of processing conditions, various types and content of additives on the performance of these toughened materials have been evaluated. The morphologies of these blend systems were evaluated through environmental scanning electron microscopy (ESEM), atomic force microscopy (AFM) and polarized light optical microscopy (PLOM) studies. The impact strength of modified PHB was increased by 440% but the modulus and consequently the stiffness of the material reduced.
Montmorillonite nanoclay platelets were introduced into the toughened blend system to regain the stiffness and modulus. Initial studies using commercially modified clay as well as pristine unmodified clay did not give promising results. Hence the clay was treated with a coupling agent to yield modified organophilic clay. This clay was incorporated into the toughened blend by melt compounding and injection molded into testing specimens. Compatiblized ‘green nanocomposites’ with 5-wt % modified clay loading showed 278% improvement in impact properties and only 40% reduction in modulus in comparison with pure PHB.   The mechanical properties of the ‘green nanocomposites’ have been correlated with theoretical model predictions. 
The incorporation of rubber particles into a brittle thermoplastic matrix is known to improve the impact properties and the toughness of the polymer. 
HIPS: homopolymer polystyrene (PS) is very brittle and the first modern high-impact PS was developed by Dow in the late 1940’s (Amos et al, US patent 2694692). Polybutadiene is mixed with styrene monomer and polymerized. 
Under proper conditions and using appropriate compatibilizers, synergistic effects arise to create high impact toughened blends. 
But adding low modulus rubber particles to the polymer lowers stiffness and strength and this reduction in rigidity significantly lowers the scratch/mar resistance of the resulting blends.

## Various Stages of Consolidation 

*Drzal et al. US Patent, 5,102,690 (1992); 5,123,373 (1992); 5,128,199 (1992)*

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## IR radiant heater

- Electrode plate

- Aligned Discontinuous Biofibers+ PP

- Sintering

- Roller
- press

- Veil/polymer film
- (Carrier film)

- BF+PP feeder/pre-aligner

- Composite Sheets for  Compression molding

*Engineered chopped fiber(BF) inlet*

- Nozzle

- Aerosol generator

- Powder PP

- Orientation chamber

*Drzal et al. US Patent 5,102,690*

***Process to make stampable formable biofiber reinforced thermoplastic sheet by the use of fine polymer particles to coat plant fibers directly at ambient temperature without solvents.***

## Nanolayer Lubricants

**NIST researchers are working to develop surface protecting and lubricating films that will shield super-small machines and their even tinier components from friction and wear. **
**Nanolayer films will be needed for the minuscule nanomachines to come. **
**The lubricating potential of a mixed-molecule, nanolayer films consisting of combinations of up to four different molecules, each one chosen to achieve desired capabilities, from wear resistance to self-repair. **
**E.g., a particular group of molecules is selected to adhere tightly to the surface, anchoring the film and protecting against high-shear collisions. Other molecules flow among the anchors to prevent friction. **

## NanoSurface Cleaning for Painting and Adhesive Bonding

- Approx. 0.88 mg Ozone required to completely oxidize 1 sq. ft. of a surface in a closed system of volume 1.8 liters (approx. 223 ppm) and contaminated with 12 monolayers of a hydrocarbon

**Interactions with surface**
- - evaporate water
- - oxidize organics
- - add functional groups
- - increase surface energy
- - change morphology
- - degrade surface
- - evolve CO2, water

## Comparison of various surface treatments

- 1 = Best       5 = Worst

*UV Treatment ~ $.01/ft**2** for polymeric surfaces.*

## Other Examples of Nanotechnology Applications for Green Manufacturing

**Manufacturing of nanoparticles using SCO****2**
**Incorporation of metal or metal oxides nanoparticles to produce coatings with anti-corrosion properties (replace chromates)**
**Self-assembled monolayers in mesoporous supports for improved selectivity in separations, reactions and sensing**
**Reversible self-assembly for end-of-life and recyclability and reuse**
**‘****Dematerialization’ through increased use of nanoscale materials to replace macroscale elements.**

***McKenzie and Hutchinson, Chemistry Today, 2004 (in press)***

## Future of Nanotechnology and Green Manufacturing?

- ‘Motivating Factors’
- Increasing environmental concern
- Carbon dioxide and VOC emissions
- Depletion of natural resources
- Limited solid waste disposal capacity
- Legislative actions
- Incentive vs Regulation
- Economic Situation
- Energy Costs

## $$$ Nanotechnology

**Worldwide research and development spending in the emerging field of nanotechnology should rise about 10 percent this year to $8.6 billion. **
**Corporations are projected to spend ~$3.8 billion on nanotechnology**
**Venture capital spending on nanotechnology ~$200 million. **
**Government spending ~$4.6 billion in research and development this year. **
**New legislation will inject $3.7 billion into nanotechnology research over four years.**
**In 2005, the private sector should outspend the public sector. **

**Lux Research Inc. (2004)**

## Principles of Green Engineering* (and Manufacturing)

**Material  and energy inputs and outputs are inherently nonhazardous as possible**
**Prevent waste rather than remediate it**
**Design Separation and Purification processes to minimize energy and materials**
**Maximize mass, energy, space and time efficiency**
**‘****Output-pull rather than ‘input-push’**
**Conserve complexity**
**Design for durability not immortality**
**Meet need, minimize excess**
**Minimize material diversity**
**Integrate local material and energy flows**
**Design for ‘commercial afterlife’**
**Use renewables rather than depletable resources**

****Green Engineering, Anastas, P.T., ACS (2000)***