Cellulose Photonics: from
nature to applications
Dr. Silvia Vignolini University of Cambridge Department of Chemistry
Photonic structures in Nature
http://prumlab.yale.edu/
The most brilliant colours in nature are obtained
by wavelength-sized transparent structures
…
iam tibi barbaricae vestes Meliboeaque fulgens purpura Thessalico concharum tacta colore,
aurea pavonum ridenti imbuta lepore
saecla novo rerum superata colore iacerent
…
De Rerum Naturae, Lucrezio, 1st-century BC Bio-inspired Photonics
SEM
2 µm
J. R. Soc. Int. 10, 20120847 (2013)
Naturwissenschaften, 100, 249 (2013)
New Phytologist, 196, 103 (2012)
J. R. Soc. Int. 9, 1295-1301, (2012) PNAS 109, 15712 (2012)
Sci. Rep. 5, 11645 (2015)
2 µm
Macromol. Chem. Physic. 214, 25 (2013)
New Phytol 205, 21 (2015) New Phytol 205, 97 (2015) Adv. Opt. Mat. (2015) DOI: 10.1002/adom.201500173
Scientific reports (2014) 4, 6075
Adv. Opt. Mat. 1 646 (2014)
ACS Appl. Mater. Interfaces 6 12302 (2014)
Outline
•  What is cellulose?
•  Cellulose colours in plants
•  Biomimetic with cellulose
Building Blocks: Cellulose
Amorphous region
Cellulose Fibre
Crystalline parts
Cellulose Molecular Structure
Carbohydrate Polymers 90, 735–764 (2012)
Cellulose'Biosynthesis''
SEM image
CELLULOSE BIOSYNTHESIS: Exciting Times for A Difficult Field of Study
Annu. Rev. Plant Physiol. Plant Mol. Biol. 1999. 50:245–76
Plant'cell'wall'
Role':'mechanical'support,'is'supposed'to'work'mainly'in'compression'
Cell wall of wood
Pollia Anatomy
1 um
SEM cross section
Structural Colour in Fruits
Pollia condensata
S. Vignolini et al. PNAS 109, 15712 (2012)
TEM cross section
Multilayered cell wall
Colour-dependent reflection
Cellulose-based Helicoid
p
p
λP≈ 2 p ncellulose
How old am I?
S. Vignolini et al. PNAS 109, 15712 (2012)
Making colour with paper
Why use cellulose to create colour?
•  Produce un-bleachable vivid colour that last for years!
•  Cellulose is the the most abundant renewable polymer
resource available •  Low cost and biocompatible (edible)
•  Fabrication by self-assembly: scalable processing 13
Nano Crystalline Cellulose
Amorphous region
Cellulose Fibre
Crystalline parts
AFM characterization
Lav ≈ 100 nm dav ≈ 5 nm
Helicoids with natural nano-crystals
Osanger transition for lyotropic liquid crystals
ni=17.6/π L2D
100
bi-phase
L. Onsager,
Ann. N.Y. Acad. Sci. 51,
627−659 (1949).
80
60
40
20
Isotropic
phase
Anisotropic
phase
ni=13.36/π L2D
0
CNC concentration
J.F. Revol , et al Int. J. Biol. Macromol. 18, 177 (1996),
J. F. Revol, et al. Int. J. Biol. Macromol. 14, 170 (1992)
Cellulose based coloured films"
Optical properties of helicoids:
500 nm
Reflectivity
0.3
0.2
10 µm
0.1
0.0
10400
µm450
450
500
550
LCP Exp.
600 Theory
650 700
750
Wavelength [nm]
Reflectivity
0.3
500 nm
area c
0.2
LCP Exp.
Theory
0.1
0.0
400
450
500
550
600
650
700
750
Wavelength [nm]
p=170 ± 10 nm & 8 layers
Thickness 1350 ± 10 nm
500
550
600
650
Wavelength [nm]
0.1
0.0
400
500 nm
area b
0.2
Theory for chiral nematic liquid crystals
ACS Appl. Mater. Interfaces 6, 12302 (2014)
p=190 ± 10 nm & 7 layers
Reflectivity
0.3
7
NEED'TO'CONTROL!'
Control of the self-assembly Camera
Optical Fiber to Spectrometer
Polarization Optics
Typical ratio of H2O-saturated
N2 to dry N2: 90%
19
Film formation dynamics
TIME of DRYING
95 hours
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101 hours
20
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Artificial Pollia Colour
100 µm
INTENSE BLUE COLOUR MADE OF CELLULOSE !!
Conclusions'
LIVING PHOTONIC
MATERIALS
NATURAL
NANO-MATERIALS
OPTICS
SELF-ASSEMBLY
Thanks'to'…'
Prof. U. Steiner
Prof. J.J Baumberg
Dr. B. Wilts
Prof. B.J. Glover
Dr. E Moyroud
Phys. and Plant Sci. Dep.
Cambridge
Dr. P. Rudall
Kew Gardens London, UK
Dr. Bruno Frka-Petesci
Dr. Gen Kamita
Dr. Ahu Parry
Giulia Guidetti
Olmpia Onelli
Rox Middleton
Lisa Steiner