Visualizing the Cellulose Microfibrils Orientation

in Bamboo and Rattan by PLRS

Jianfeng Ma

Research Institute of Bamboo & Rattan Biomass New Materials, ICBR

“Plant Steel”

• A natural functionally-graded biocomposite material• Excellent load-bearing properties

Cellulose Biosynthesis and Assembly

Composition and structure according to function

Primary cell wall Cellulose fibrilsHemicelluloses Pectins

flexible and elastic

Secondary cell wall Cellulose fibrils HemicellulosesLignin

S1

primary wall

S2

S3

Middle lamellaLigninSmall amount of carbohydrates

Cellulose Biosynthesis and Assembly

Cosgrove., 2005, Nature Review.

Simon et al., 2018.

Hexameric particle rosettes

Cellulose synthase protein

Fiber Parenchyma

Bamboo Cellulose Nano-crystal

Samples P-CNC F-CNC

CrI (%) 50.86 54.87

Crystal size(nm)

2.17 2.08

Lattice distance (nm)

0.395 0.399

55% H2SO4

50°C , 1.0h

From Cellulose Chains to Microfibrils

Cellulose Chain Cellulose Nanocrystal Cellulose Microfibrils

Highly organized cellulose microfibrils

Disordered cellulose microfibrils

Mechanical Properties of Natural Cellulose

Young’s modulus is roughly 130 Gpa Tensile strength is close to 1 GPa

Gibbson, 2012. Journal of Royal Society Interface.

LM: El-Osta (1973, Mercury impregnation) ; Senft & Bendtsen (1985, , iodine impregnation)

PLM: Praynard (1954); Echolls (1955); Oldenburg (2007); Elbaum (2015)

XRD: Wardrop (1951); Watson & Dadswell (1964); Sahlberg (1997); Yang (2015)

SEM: Saka (1982); Westermark (1988); Xu (2006); Zheng (2017)

TEM: Leise (1956); Donaldson (1999); Singh (1999,2002); Fromm (2003); Ma (2015)

AFM: Cosgrove (2005, 2007, 2012, 2016) ; Ding (2012, 2014); Kafle (2014); Fei (2015)

SAXS/WAXS/SANS/WANS: Lichtenegger (1999) ; Jarvis (2015); Fei (2015)

FT-IR Microscopy: Schmidt (2006); Gierlinger (2007); Salmen (2011); Chang (2014)

Confocal Raman Microscopy: Atalla (1985, 1986); Gierlinger (2010); Xu (2015); Sun (2016)

SFG: Cosgrove & Kim (2017, 2018)

Cell Wall Imaging Techniques

Notburga Gierlinger. 2012, Journal of Experimental Botany.

Microfibrils Orientation

Electromagnetic Band

Ultravioletmicrospectrophotometry

Confocal laser scanning micro? scopy FT-IR microspectroscopy

Confocal Raman microspectroscopySpatial resolution=0.35 um

UMSP CLSM CRM FT-IR microspectroscopy

Jin et al., 2017, Spectra and Spectral analysis.

Raman Spectra from Lignocellulosic Biomass

Pinus

Poplar

M. sinensis

Bamboo

Rattan

Raman shift (cm-1)

Ram

an in

tensity (cts)

Wavenumbers

(cm-1) Component Assignment

2 945 Lignin C-H stretching in OCH3 asymmetric

2 897 Cellulose C-H and C-H2 stretching

1 655 Lignin Ring conjungated C=C stretching of coniferyl/sinapyl

alcohol; C=O stretching of coniferaldehyde/sinapaldehyde

1 600 Lignin Aryl ring stretching symmetric

1 464 Lignin and Cellulose HCH and HOC bending

1 423 Lignin O-CH3 deformation; CH2 scissoring; guaiacyl ring vibration

1 378 Cellulose HCC, HCO and HOC bending

1 330 Lignin? Aryl-OH or aryl-O-CH3 vibration?

1 274 Lignin Aryl-O of aryl-OH and aryl O-CH3; guaiacyl ring (with C=O

group) mode

1 173 Hydrocinnamic acids C-O stretching of Hca

1 140 Lignin? C-O-C stretching asymmetric?

1 122 Cellulose, Xylan, and

Glucomannan

Heavy atom (CC and CO) stretching

1 098 Cellulose Heavy atom (CC and CO) stretching

902 Cellulose Heavy atom (CC and CO) stretching

520 Cellulose some heavy atom str.

438 Cellulose some heavy atom str.

380 Cellulose some heavy atom str.

Peak Assignments

Atalla and Agarwal, 1986, Planta.

Evidence for orientation is detected through Raman intensity variation is detected from rotations of the exciting electric vector respect to cell wall geometry.

The cellulose pyranose rings of the anhydroglucose repeart units are in plane perpendicular to the cross section, while methine C-H bonds are in planes parallel to the cross

Cellulose Microfibrils Orientation

Polarized light

Cellulose chain

When the molecular vibrational direction are more parallel to the laser polarizationdirection the corresponding band intensity is enhanced.

Cellulose Microfibrils Orientation

Atalla and Agarwal., 1985, Science.

Atalla, et al., 1980, Macromolecules.

Polarized light direction

MFA

MFA

Raman images showing the MFA within the multilayer structure of thick walled bamboo fiber, 1080-1120 cm-1.

Mfs Orientation Bamboo Fiber Wall

Rattan Resources and Utilizaiton

Sheath Cane Seed

17

Bright view image (Left), overall morphology (Middle), lignin (blue) and cellulose (red) overlaid Raman image.

Cellulose (red), lignin (Middle) and overlaid Raman image.

Cellular Level Heterogeneity of components distribution

Polarized laser direction along the radial wall

Variation in Raman band intensity of broad and narrow wall layer.

Mfs Orientation Rattan Fiber Wall

C-O-C, 1095 cm-1

Mfs Orientation Rattan Fiber Wall

R= I1095/I2897

R: Vessel Secondary Wall>Fiber Narrow Layer >Fiber Broad Layer

An outermost primary wall composed of a meshwork of Mfs

The secondary wall containing Mfs mainly arranged in a parallel orientation

C-O-C CH,CH2

Mfs Orientation Rattan Vessel

Chanllenges

Fluorescence background

Spatial Resolution & Chemometrics

Quantitative analysis of cellulose microfibrils

orientation

Outlook

combination of Atomic force microscopy (AFM) +Raman

surface and materialproperties on the nanolevel

Molecular compositionon the microlevel+

II

(I) (II)

Acknowledgements

Funding:

National Key R&D Program of China (2017YFD0600804) National Natural Science Foundation of China (31500497)Fundamental Research Funds of ICBR (1632017014)

Group People :

Prof. Xinge LiuProf. Shumin YangDr. Genlin Tian Dr. Lili Shang

Jianfeng MaInternational Center for Bamboo and RattanMajf@icbr.ac.cn+86-15101509897

Thanks a lot