Laser Nanostructuring of Soft Matter - University of · PDF fileLaser Nanostructuring of Soft Matter ... TFTs, OLEDs, sensors, energy harvesters, etc. ... model polyimide rough surface

Laser Nanostructuring of Soft Matter

Marta Castillejo

Instituto de Química Física Rocasolano, CSIC

Madrid, Spain

School on Lasers in Materials Science July 2012, Isola di San Servolo

Consejo Superior de Investigaciones Científicas Spanish Council for Scientific Research (CSIC) Largest public research organization in Spain

Instituto de Química Física Rocasolano

Madrid

Lasers, nanostructures and materials processing

Instituto de Química Física Rocasolano, CSIC

Obtain new knowledge on physicochemical control mechanisms of micro- and nanofabrication of different types of materials using processing techniques based on irradiation and ablation with pulsed lasers in ns and fs domains.

Research of interest in technological areas of photonics, photovoltaics, nonlinear optics, biomedicine and cultural heritage.

Fabrication of Thin Films and Nanostructures by Pulsed

Laser Deposition

Lasers in Conservation of Cultural Heritage

http://lanamap.iqfr.csic.es

Laser micro- and nanostructuring

Ablation Mechanisms and Plume Dynamics

Soft Matter

Soft

Mat

ter

7(2

0),

20

11

|

Nanostructuring

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Pulses of 130 as, CUSBO, Milan

T4 Bacteriophage, 25,000X

Soft Matter

What is it? polymers, colloids, foams, gels, liquid crystals, wide variety of self-organizing materials

Basic properties Materials with length scales much

larger than molecules, Many degrees of freedom: Properties

dominated by thermal fluctuations, Easily deformed by applied external

stresses. http://physics.oulu.fi

Mesoscopic size ≈ 100 nm

Soft Matter

Why is it interesting?

Unpredictable behaviour from molecular constituents due to self-organization into mesoscopic structures (reveals quantum mechanical properties).

Electronic, optical properties differ from bulk material due to quantum confinement effects.

Physics meets Chemistry meets Biology. Science (2009) 323, 237

Who started it all? P. G de Gennes Nobel Prize, 1991 For discovering that "methods developed for studying order phenomena in simple systems can be generalized to more complex forms of matter, in particular to liquid crystals and polymers“.

http://www.nobelprize.org

Geckos

Correlation between Multiscale Structure and Property

http://biomaterials.bme.northwestern.edu

Inspiration and Learning from Nature

Learning from Nature to develop novel functional (soft) materials bioinspired, multiscale structured materials, bio-nanomaterials (bio-nanoparticles), hybrid organic/inorganic implant materials, smart biomaterials.

Adv. Mat. 2008, 20, 2842

Correlation between Multiscale Structure and Property

Ad

v. F

un

ct. M

ater

. 20

12

, 2

2, 1

24

6

Gecko-inspired angled elastomer micropillars

Soft Matter

Soft

Mat

ter

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0),

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Nanostructuring

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Variety of key techniques used extensively for generating structures at the

nanoscale. Nanofabrication

Some limitations

Spatial resolution,

Based in multiple-steps procedures,

Involve use of clean-room facilities,

Difficult to scale to wafer-like sizes.

Martín et al., Macromolecules,42 (2009) 5395.

Fluoropolymer NTs

templated by AAO

Nanoporous alumina

membranes (AAO

templates)

Inorganic templates

Nanoimprint Lithography (NIL)

LIPSS

LIFT

PLD

MAPLE 2-3 PP

OTAN

Others

Precise, non-contact, flexible set-ups: all environments, all materials

Ability to manipulate micro- and nanoscale,

Control of the physicochemical behaviour of treated material,

Specific advantages of ultrashort pulses (fs)

Laser Nanofabrication

A wealth of laser-based tools and methods with specific capabilities

Laser printing fabrication of various types of components:

TFTs, OLEDs, sensors, energy harvesters, etc.

http://www.e-lift-project.eu

Polymer coated sensor arrays

Organic Light Emitting Diodes

Laser Induced Forward Transfer (LIFT)

Neural tissue engineering 3D scaffolds, Biofabrication 3 (2011) 045005

High-res 3D scaffolds on biomaterials and biocompatible materials for tissue engineering

Two-photon polymerization of hybrid materials for nanophotonics

http

://ww

w.p

ho

ton

ics4life.eu

Multiphoton polymerization

http

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w.sigm

aaldrich

.com

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Optical trap assisted nanopatterning (OTAN)

AFM image of MAPLE-deposited polymer glass, Nature Mat., 2012 ; DOI 10.10.38

Later in this School! PLD, MAPLE

Pattern nanoscale features on model polyimide rough surface. Taking advantage of plasmonic field

enhancement. IOP Nanotech., 23 (2012) 165304.

Nanopatterning on rough surfaces using optically trapped microspheres

Polymers

Fundamental components of soft matter.

Intrinsic structure of semicrystalline polymers: alternate nm size regions of crystalline/ amorphous phases. http://www.polymerexpert.biz

Small 2011, 7, 1288

Nanoconfinement in polymeric materials

Large effects on structure/ dynamics

Affect phase transitions/ physical processes

Crucial for development of materials for specific applications

Critical for applications as efficient structural materials

Improve chain design,

Tuning semicrystalline structure,

Control of nanostructure by confinement in nm range.

Polymers

2D meshed microfluidic channels

inside IPL polymer fabricated by 2PP

method, Light: Science & Applications

(2012) 1, doi:10.1038/lsa.2012.6

Switchable Diffraction Gratings,

Adv. Funct. Mat. 18 (2008) 1617

Electro-optic activity of

nonlinear optical polymer,

Polymer Chem 50 (2012)

1254.

Applications of nanoconfined polymer and biopolymer materials

Photonics and Photovoltaics,

High-density magnetic data storage devices

Microchip reactors

Biosensing and Biomedicine

Thin microstructured plastic

sheet on solar panel to

increase light absorption

(Genie Lens Technologies)

Fabrication of wafer-scale

polystyrene photonic crystal,

J. Mat. Chem. 2011, 37.

Laser Nanostructuring of Polymers: Bubbles, Ripples

and Applications

1. Laser Foaming

2. Laser Induced Periodic Surface Structures (LIPSS)

3. Applications: tissue engineering and SERS

(a) (b)(a) (b)Synthetic polymers Polycarbonate Bis Phenol A (PC)

Poly (ethylene terephthalate), (PET) x=2

Poly (trimethylene terephthalate), (PTT) x=3

Poly (vinyliden fluoride), (PVDF)

(a) (b)(a) (b)

LIPSS on polymers and biopolymers

Biopolymers

Chitosan

Collagen

Gelatine

Starch

ω ω

Thin films by spin coating

Thickness ~ 150 nm

Ra< 1 nm


Thin films preparation

Self-standing films by dropcasting

Thickness ~ 20-200 mm


and Applications

1. Laser Foaming



20 mm

Gelatine Tiitanium: sapphire laser

800 nm, 90 fs

Laser submicro-foaming by irradiation with fs pulses

Appl. Surf. Sci., 253 (2007) 642. Appl. Surf. Sci. 254 (2007) 1179. Appl.Phys A, 93 (2008) 2009

5 mm 5 mm

Single pulse laser treatment yields a foamy layer with nanofibrous properties

Mimicks nanostructure of fibrillar network of living tissues.

800 nm, 3.2 J/cm2

400 nm, 1.5 J/cm2 400 nm, 1.9 J/cm2

266 nm, 0.2 J/cm2 266 nm, 2.2 J/cm2

800 nm, 2.2 J/cm2

10 mm

800 nm, 2.2 J/cm2

Pores or bubbles have a size of the order of the irradiation wavelength.

Most of the time interconnected: of interest for potential biomedical applications.

Collagen Gelatine

Appl. Surf. Sci., 253 (2007) 642.

Ti:Sa laser, 90 fs

Laser submicro-foaming by irradiation with fs pulses

10 mm

Laser foamed chitosan

50 mm

Cell culture of

mouse NIH/3T3

fibroblasts

Laser foamed chitosan for cell culture

Lamellipodia

Chitosan film, one pulse, 248 nm, 20 ns, 2 J/cm2, cell culture of 3 days

Cell

density/

num

ber

of cells

/m

m2

Days of culture

Non-irradiated Irradiated

Castillejo et al., Appl. Surf. Sci. 2012, 258, 8919.

Foamed chitosan as substrates for substrates for cell culture

Fibroblast cells


and Applications

1. Laser Foaming



Contribution of several processes

Non-thermal chain scissoring and migration

Amorphization of crystalline domains

Temperature increase above Tg

Photoxidation, …

Fi

The classical mechanism

isin

n

Fs regime

Extensive work in different materials

(metals, SCs)

Very few studies on polymers

Studies needed for assessment of

mechanisms


In air, linearly polarized Wavelength Pulse duration

ArF excimer

Nd:YAG (4th harmonic)

Nd:YAG (5th harmonic)

193 nm

213 nm

266 nm

15 ns

15 ns

6 ns

Ti:sapphire (3rd harmonic) 265 nm 260 fs

Ti:sapphire 795 nm 120 fs


Rebollar et al.:

Annual report HASYLAB , 2010.

Langmuir, 2011, 27, 5596.

Appl. Phys. Lett. 2012, 100, 041106

Martín-Fabiani et al. Langmuir 2012, 28, 7938.

STRUCTURAL ANALYSIS

AFM: Real space

Grazing Incidence X ray diffraction: Reciprocal space

qz

qy

a

w

ai

LIPSS filmm

m (qy =0)

h

(a = 0)

Direct X-ray beam

Incident X-

ray beam

ai

h

yq

2

Structural analysis by Grazing Incidence X-Ray Scattering

GISAXS: Two orthogonal scattering vectors:

structural correlations

BW4 beamline, HASYLAB (DESY, Hamburg)

0.13808 nm, ai= 0.4 º

a exit angle

w out of

scattering

plane angle

aa

sinsin

2 izq

┴ to film plane

a

cos

2 senqy

‖ to film plane

5x5 mm2

fs-LIPSS

ns-LIPSS

LIPSS on polymers and biopolymers Parallel to laser polarization

Period≈ wavelength

0 1000 2000 3000 40000

100

200

300

AFM

GISAXS

L (

nm

)

Number of pulses

4 6 8 10 12 140

100

200

300

AFM

GISAXS

L (

nm

)

Fluence (mJ/cm2)

(a)

(b)

(b) 100 (c) 300

(d) 600 (e) 1200 (f) 6000

mm

mm

mm

mmmm0 0 0

0 02 2

2 2 2

0 2mm0 0 0

0 0 0

160 160 160

160 160 160

nm

nm

(a) Non-irrad.

PTT, 266 nm, 6 ns,7 mJ/cm2 LIPSS Period

10x10 mm2

Periods ≈ laser wavelength

Good correlation AFM and GISAXS (validation)

Martín-Fabiani et al. Langmuir 2012, 28, 7938.

PVDF, 266 nm, wide

range of fluences

10 nm

-10 nm

10 nm 300 nm

-300 nm

40 nm

-40 nm

20 nm

-20 nm

100 nm

-100 nm

(a) non-irrad. (b) 85 mJ/cm2 (c) 140 mJ/cm2

(d) non-irrad. (e) 7 mJ/cm2 (f) 13 mJ/cm2

PVDF

PTT thermally treated

-10 nm0 1 2 3 40

1

2

3

4

mm

mm

0 1 2 3 40

1

2

3

4

mm

mm

0 2 4 6 80

2

4

6

8

mm

mm

0 2 4 6 80

2

4

6

8

mm

mm

0 10 20 30 400

10

20

30

40

mm

mm

0 1 2 3 40

1

2

3

4

mm

mm

No LIPSS in

semicrystalline

polymers

PTT, 266 nm,

No Bragg reflections: no LIPSS-

induced crystallization

2D-GIWAXS: information on crystalline

structure and crystal orientation

7 mJ/cm2, 106 mJ/cm2

PTT, 532 nm

No LIPSS at

weakly

absorbed

wavelengths

6000 pulses

6 ns pulses

• LIPSS in amorphous polymers when T>

Tg (surface devitrification).

• Weakly absorbing polymers T< Tg.

• Crystalinity prevents softening necessary

for LIPSS.

Temperature increase: Solving the one-dimensional

heat conduction equation

0 100 200 300 400 500 60020

40

60

80

100

120

140

160Tg

9 mJ/cm2

Te

mp

era

ture

/ o

C

Time/ ns

0 nm

30 nm

100 nm

140 nm

5 mJ/cm2

0 100 200 300 400 500 60020

30

40

50

60

70

80Tg

5 mJ/cm2

Te

mp

era

ture

/ 0C

Time/ ns

0 nm

30 nm

100 nm

140 nm

3 mJ/cm2

(a) PET

(b) PC

(c) PVDF

0 100 200 300 400 500 60020

30

40

50

60

140 mJ/cm2

0 nm

Te

mp

era

ture

/ o

C

Time/ ns

0 100 200 300 400 500 60020

40

60

80

100

120

140

160Tg

9 mJ/cm2

Te

mp

era

ture

/ o

C

Time/ ns

0 nm

30 nm

100 nm

140 nm

5 mJ/cm2

0 100 200 300 400 500 60020

30

40

50

60

70

80Tg

5 mJ/cm2

Te

mp

era

ture

/ 0C

Time/ ns

0 nm

30 nm

100 nm

140 nm

3 mJ/cm2

(a) PET

(b) PC

(c) PVDF

0 100 200 300 400 500 60020

30

40

50

60

140 mJ/cm2

0 nm

Te

mp

era

ture

/ o

C

Time/ ns

PET

PVDF

266 nm, 6 ns

Tg= -35 ºC

Tm= 248 º C

Tg= 75 ºC

Tm= 252 º C

ns-LIPSS on polymers: Mechanisms?

Rebollar et al, Langmuir, 2011, 27, 5596.

(a) Non-irrad.

(b) 300 pulses

-40 nm

80 nm

-90 nm

9 nm

-5 nm

50 nm

-50 nm

40 nm(c) 700 pulses

(d) 1200 pulses

10 nm

-10 nm

10 nm 300 nm

-300 nm

40 nm

-40 nm

20 nm

-20 nm

100 nm

-100 nm

(a) non-irrad. (b) 85 mJ/cm2 (c) 140 mJ/cm2

(d) non-irrad. (e) 7 mJ/cm2 (f) 13 mJ/cm2

PVDF

PTT thermally treated

-10 nm0 1 2 3 40

1

2

3

4

mm

mm

0 1 2 3 40

1

2

3

4

mm

mm

0 2 4 6 80

2

4

6

8

mm

mm

0 2 4 6 80

2

4

6

8

mm

mm

0 10 20 30 400

10

20

30

40

mm

mm

0 1 2 3 40

1

2

3

4

mm

mm

Ei≈ 6.5 eV 413 nm

265 nm 795 nm

e plasma energy density

r density

Cp heat capacity

pCT

r

e icr E

4

9re

rcr critical free

electron density

Vogel et al.. Appl. Phys. B (2005)

2

0

2)/2(

e

mccr

er

mc mass of quasi-free

electron in conduction band

Rebollar et al., Appl. Phys. Lett. 2012, 100, 041106

Generation of free electrons by MPI

fs-LIPSS on polymers: Mechanisms?

T scales inversely with : T265 ≈ 10XT795

larger N and F needed for LIPSS at longer

Further morphological control of nanostructures

Dependence of LIPSS period with

angle of incidence

)sin(

n

Structures using

circularly polarized light

5x5 mm2

PET, 266 nm, 6 ns,

7 mJ/cm2, 1200

Gold-coated polymer LIPSS as substrates for SERS

Ns-PLD, 213 nm,

2 J/cm2

PET, PTT LIPSS substrates 0 10000 20000 30000 40000

0

10

20

30

40

50

Deposit t

hic

kness (

nm

)

Number of pulses

Gold layer preserves LIPSS relief

Tests with

Benzenethiol

Gold-coated LIPSS for SERS

Raman signal enhancement:

10 nm gold layer on LIPSS

950 1000 1050 1100

36000 pulses

24000 pulses

Inte

nsity (

arb

.units)

Wavenumber (cm-1)

12000 pulses

BT 10-5 M

Raman signal depends on

Thickness of gold layer

Analyte concentration

10-6

10-5

10-4

10-3

2000

3000

4000

[BT] (M)

Tests with

Benzenethiol

Rebollar et al., submitted.

Enhancement factor of 8 orders of

magnitude

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Laser Nanostructuring of Soft Matter - University of · PDF fileLaser Nanostructuring of Soft Matter ... TFTs, OLEDs, sensors, energy harvesters, etc. ... model polyimide rough surface