Supporting Information

� Wiley-VCH 2014

69451 Weinheim, Germany

Bioinspired Green Composite Lotus Fibers**Mengxi Wu, Hua Shuai, Qunfeng Cheng,* and Lei Jiang

anie_201310656_sm_miscellaneous_information.pdf

Supporting Information

0

10

20

30

40

50

60

3.0 7.06.05.04.02.0Diameter (μm)

Frac

tion

(%)

Figure S1. The diameter of lotus fibers distribute in the range of 3.0-6.0 μm, and the average of lotus fibers can be calculated about 5.0 μm.

Figure S2. The digital photograph of the continuously collected bioinspired green composite fiber (GCF) on the stick.

Figure S3. The SEM images show the twisted single (a), double (b), triple (c), and quadruple (d) lotus fiber bundles. e) the twisted whole

lotus fiber bundles from one stem.

0 2 4 6 8 100

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500

Stre

ss(M

Pa)

Strain(%)

c)

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500

Stre

ss(M

Pa)

Strain(%)

a)

0 2 4 6 8 100

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500

Stre

ss(M

Pa)

Strain(%)

d)

0 2 4 6 8 100

100

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Stre

ss(M

Pa)

Strain(%)

b)

0 2 4 6 8 100

100

200

300

400

500

Stre

ss(M

Pa)

Strain(%)

e)

Figure S4. The corresponding tensile stress-strain curves of twisted LF bundles: a) single, b) double, c) triple, d) quadruple and e) the whole

LF bundles from one stem.

Figure S5. SEM images of pure lotus fiber with different twist angles: a) 10 ± 2o, b) 15 ± 1.5 o, c) 20 ± 3o, and the diameter is about 60 μm.

0 200 400 600 8000

20

40

60

80

100

Wei

ght l

oss

(%)

Temperature (oC)

PVA LF GCF-I GCF-II GCF-III

Figure S6. TGA curves of pure PVA, lotus fiber (LF) and three kinds of lotus composite fibers (GCF-I, GCF-II and GCF-III). The PVA

almost decomposes at around 800 ºC (black curve) and the LF remains about 6.7 %. The other three composite fiber remains about 6 %,

5.2 %, and 4.2 %, corresponding to GCF-I (blue curve), GCF-II (green curve), and GCF-III (magenta curve), respectively. Thus, the PVA

loading in the composite fiber is calculated to be about 10.4 wt%, 22.4 wt%, and 37.3 wt%, respectively.

Figure S7. SEM images of GCF: a) and b) is the surface morphology of GCF-I, shows the PVA is not enough for condensing the lotus fiber.

c) and d) GCF-II shows the better interface between PVA and lotus fiber. e) and f) GCF-III shows much more PVA on the surface of lotus

fiber.

0 1 2 3 4 5 6 70

200

400

600

800 LF GCF-I GCF-II GCF-III

Strain (%)

St

ress

(MPa

)

Figure S8. Tensile stress-strain curves of lotus fiber (black curve) and composite fibers of GCF-I (red curve), GCF-II (blue curve), and GCF-

III (green curve): the tensile strength and Young’s modulus of lotus fiber are about 329.4 ± 28.6 MPa and 6.3 ± 1.2 GPa, respectively. After

introducing the PVA, the mechanical properties of composite fiber dramatically increase. The tensile strength increases to 439.5 ± 109.9

MPa, 622.5± 60.3, and 559.3 ± 54.8 corresponding to GCF-I, GCF-II, and GCF-III, respectively. And the Young’s modulus reaches 10.8 ±

5.6 GPa, 22.4 ± 2.9 GPa, and 19.1 ± 3.7 for GCF-I, GCF-II, and GCF-III, respectively.

Figure S9. Tensile stress-strain curves of pure PVA film and PVA with different treatments including . glutaraldehyde (GA) and heated. The

pure PVA film shows tensile strength of 76.1 ± 4.2 MPa, Young’s modulus of 2.4 ± 0.3 GPa, and strain of 456.5 ± 87.9% (black curve).

After cross-linking with GA, the tensile strength increases to 93.6 ± 14.9 MPa (red curve), and 118.2 ± 35.3 MPa (blue curve) for different

ratio with GA of 0.1 and 1, respectively. Compared to GA cross-linking, the heat treatment (60 oC/2h) enhances the tensile strength to 148.8

± 7.3 MPa, however, the strain dramatically decreases to 42.5 ± 15.8 % (magenta curve). Combining the heat treatment and GA (ratios of 0.1

and 1), the tensile strength of treated PVA can reach 142.9 ± 4.2 MPa (green curve) and 202.7 ± 41.2 MPa (orange curve), which is 1.88 and

2.66 times than that of pure PVA, respectively.

4000 3500 3000 2500 2000 1500 1000Wavenumbers (cm-1)

Heated and GA treated GCF

GA treated GCF

GCF

LF

PVA

Figure S10. FTIR spectrum of pure PVA, LF, GCF, GA treated GCF and combination of heated and GA treated of GCF. The characteristic

peaks of secondary alcohol around 1100 cm-1

disappear, indicating the successful cross-linking by GA.

Table S1. The mechanical properties of the twisted LF bundles.

Specimen No. Tensile strength (MPa)

Young’s modulus (GPa)

Strain (%) Toughness (MJ/m3)

Twisted single LF bundle

1 439.2 9.4 8.4 21.7

2 436.4 12.7 4.5 11.2

3 407.5 10.5 4.0 8.2

Average ± SD 427.7 ± 17.5 10.9 ± 1.7 5.6 ± 2.4 13.7 ± 7.1

Twisted double LF bundle

1 415.5 20.9 4.05 9.73

2 405.3 11.0 4.86 10.92

3 323.8 13.9 4.15 7.84

Average ± SD 381.5 ± 50.3 15.3 ± 5.1 4.4 ± 0.4 9.5 ± 1.6

Twisted triple LF bundle

1 191.34 8.0 4.72 5.36

2 244.82 10.6 4.96 7.45

3 197.21 14.7 6.51 8.95

Average ± SD 211.1 ± 29.3 11.1 ± 3.4 5.4 ± 1.0 7.3 ± 1.8

Twisted quadruple LF bundle

1 198.0 8.1 4.2 5.0

2 156.6 5.3 7.5 6.3

3 169.1 6.9 4.5 4.9

Average ± SD 174.6 ± 21.2 6.8 ± 1.4 5.4 ± 1.8 5.4 ± 0.8

Twisted LF bundles from one stem

1 308.1 5.2 4.5 7.4

2 318.2 6.1 4.2 7.3

3 361.9 7.6 4.6 8.1

Average ± SD 329.4 ± 28.6 6.3 ± 1.2 4.4 ± 0.2 7.6 ± 0.4

Table S2. Mechanical properties of natural fibers and bioinspired green composite fibers.

Specimen Density (g/cm3

Tensile strength (MPa) )

Young’s modulus (GPa)

Elongation (%)

Specific tensile strength (σ/ρ, kN·m/kg)

Specific modulus (E/ρ, MN·m/kg)

References

Flax fiber 1.5 345-1035 27.6 1.2-3.2 230-690 18.4 [1]

Cotton fiber 1.5-1.6 287-800 5.5-12.6 3.0-10.0 179-500 3-8

Jute fiber

[7a, 8, 25]

1.3-1.5 393-800 10-55 1.5-1.8 262-533 7-37

Hemp fiber

[7a, 8, 25]

1.5 550-900 70 1.6 367-600 47

Sisal fiber

[7a]

1.3-1.5 511-635 9.4-28 2.0-2.5 340-423 6.3-18.7

Ramie fiber

[7a, 8, 25]

1.5 400-938 44 2.0-3.8 267-625 29.3

Coir fiber

[7a, 25]

1.2 131-220 4-6 15-30 109-183 3.3-5

Cocoon silk

[7a, 8, 25]

1.3-1.4 620.5 7 14.5 443.2 10.4

Lotus fiber

[13]

1.18 230-340 6 5-7 195-288 4.2-5.9

Our work Bioinspired green composite fiber

1.19 675-749 45 2.1 629 37.8