나노 기술의 이해

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나노나노 기술의기술의 이해이해

(Understanding Nanotechnology) (Understanding Nanotechnology)

Prof. Kahp

Prof. Kahp - - Yang Suh Yang Suh

School of Mechanical and Aerospace Engineering School of Mechanical and Aerospace Engineering

Seoul National University

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Lecture 4.

Problems and Challenges Problems and Challenges

in Nanotechnology

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Lecture Review Lecture Review

Lecture 1 Lecture 1

History of Nanotechnology

- Definition of Nano Size - Feynman’s Lecture

Lecture 2 Lecture 2

Introduction to Nanotechnology

- Definition of Nanotechnology

- Briefing about the Advancement of Nanotech.

Lecture 3 Lecture 3

Scanning Probe Microscope

- STM

- SEM, TEM

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Fundamental Problems in Nanotech.

Biological & Environmental Problems Biological & Environmental Problems

Social Responsibility, ethics…

Uncertainty of Nano-scale phenomenon

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Biological & Environmental Problem Biological & Environmental Problem

z Past failures to consider environmental consequences early have been costly:

9 semiconductor industry (metals, solvents) 9 synthetic chemicals (PCB, DDT, Freon)

9 applications of natural compounds (chlorine, asbestos)

9 transportation, energy (air pollution, global warming, nuclear wastes)

z Small adjustments early in the trajectory of a technology have large consequences.

z Must introduce the environmental perspective early into the culture of emerging technologies (research and educational missions).

Ozone hole

What – Me Worry ?

Lessons from Earlier Technologies

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Biological & Environmental Problem

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Biological & Environmental Problem Biological & Environmental Problem

Nanoparticles may enter living cells via:

9 Endocytosis

Receptor activation for initiation

9 Membrane penetration

Generally occurs with very hydrophobic par ticles

9 Transmembrane channels

May be seen with very small nanoparticles (< 5 nm?)

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Biological & Environmental Problem Biological & Environmental Problem

Inhalation: Inhaled particles induce inflammation in respiratory tract, causing tissue damage.

Example: Inhalation of silica particles in industrial workers causes “silicosis”.

Dermal exposure: Particles may enter body through the skin. Potential hazards are

unknown at present.

Ingestion: nanoparticles may cause liver damage. Ingested nanoparticles (i.e. for oral drug delivery) have been found to accumulate in the liver. Excessive immune/inflammatory responses cause permanent liver damage.

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Biological & Environmental Problem Biological & Environmental Problem

z Accumulation of a substance within a species due to lack of degradation or excretion

z Most nanoparticles are not biodegradable

z If nanoparticles enter organi sms low in the food web, the y may be expected to accum ulate in organisms higher in the food web

Bio Accumulation & Bio Uptake

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Biological & Environmental Problem Biological & Environmental Problem

z Accumulation of a substance within a species can occur du e to lack of degradation or excretion.

z Many nanoparticles are not biodegradable.

z If nanoparticles enter organisms low in the food web, they may be expected to accumulate in organisms higher in the food web.

Very little is understood about possible health effects

of nanoparticle exposure !!

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Uncertainty of Nano

Uncertainty of Nano - - scale phenomenon scale phenomenon

< Aggregation >

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Uncertainty of Nano

s = 1

S = 6 S = 12

s = 1/4 s = 1/16

S = 24

Surface area ↑ , Reactivity ↑

Main reason of Aggregation

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Uncertainty of Nano

Ex) CNT(Carbon Nano Tube)

- Young’s modulus : 1.2 terra pascals - Light weight

- Thermal conductivity - Electrical conductor - Composed by C60

< Toxicity with Usefulness >

Bring about Cancer

DNA damaged

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Uncertainty of Nano

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Uncertainty of Nano

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Uncertainty of Nano

< Same material Different color >

Ex) Quantum Dot

Is there any possibility of misuse??

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Social Responsibility, ethics Social Responsibility, ethics … …

Need Understanding & Responsibility Need Understanding & Responsibility

“Military applications of molecular manufacturing have eve n greater potential than nuclear weapons to radically ch

ange the balance of power.”

Admiral David E. Jeremiah, USN (Ret) Former Vice Chairman, Joint Chiefs of Staff November 9, 1995

“Even with all its unknowns, even with all its perils and risks , who’d say no to nano?”

Ed Regis, author of Nano, the emerging science of nanotechnology:

remaking the world – molecule by molecule, 1995, p.308

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Social Responsibility, ethics Social Responsibility, ethics … …

Need Understanding & Responsibility Need Understanding & Responsibility

“If everyone has this technology, then if it can be abused,

it will be abused.

And if it can destroy the biosphere, that's threat enough for me.”

K. Eric Drexler

“Our most powerful

21st-century technologies : robotics, genetic engineering and nanotech are threatening

to make humans

an endangered species.”

Bill Joy

http://www.wired.com/wired/archive/8.04/joy.html

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For the next step For the next step

Size Size Down Down

to to Nano Nano

Ability Ability

to to Control Control Political Political Investment Investment

Keep In Mind !!

The Fundamental Problems

Of Nanotechnology

Nano Nano Physics Physics

Nano Nano Application Application

Nano Nano

Fabrication