Stimuli-responsive mechanically adaptive polymer nanocomposites

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Stimuli-Responsive Mechanically Adaptive Polymer Nanocomposites

Electronic Supporting Information

Kadhiravan Shanmuganathan,^† Jeffrey R. Capadona,^‡,Ψ Stuart J. Rowan,^*†,§ and Christoph Weder^*†,#

Department of Macromolecular Science and Engineering, Case Western Reserve University (CWRU), 2100 Adelbert Road, Cleveland, OH 44106. Department of Biomedical Engineering, CWRU, 10900 Euclid Avenue, Cleveland, OH 44106. Rehabilitation Research and Development, Louis Stokes Cleveland DVA Medical Center, 10701 East Blvd., Cleveland, OH 44106. Department of Chemistry, CWRU, 2100 Adelbert Road, Cleveland, OH 44106 USA. Adolphe Merkle Institute and Fribourg Center for Nanomaterials, University of Fribourg, CH-1700 Fribourg, Switzerland.

† Department of Macromolecular Science and Engineering, CWRU.

‡ Department of Biomedical Engineering, CWRU.

Ψ Rehabilitation Research and Development, Louis Stokes Cleveland DVA Medical Center.

§ Department of Chemistry, CWRU.

# Adolphe Merkle Institute and Fribourg Center for Nanomaterials, University of Fribourg.

* To whom correspondence should be addressed. E-mail: [email protected];

[email protected]

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Figure S1. (a) Tensile storage moduli E′ of dry films of neat PVAc and PVAc/tunicate whisker (TW)

nanocomposites as a function of temperature and composition: 0% v/v TW (U), 0.8% v/v TW (

○

^{), 4%}

v/v TW (

□

), 8.1% v/v TW (▲), 12.2% v/v TW (

●

), 16.5% v/v TW (

■

). Data were acquired by dynamic mechanical analysis (DMA). (b) Tensile storage moduli E′of ACSF-swollen (for 1 week at 37

°C) films of neat PVAc and corresponding PVAc/tunicate whisker (TW) nanocomposites. Reprinted with permission from ref 11b. Copyright 2009 Elsevier.

30 40 50 60 70 80 90

10⁵ 10⁶ 10⁷ 10⁸ 10⁹

E' (Pa)

Temperature(°C)

(a)

20 30 40 50

0 100 200 300 400 500 (b)

E' (MPa)

Temperature(°C)

3

15 20 25 30 35 40 45 50

0.35 0.40 0.45 0.50 0.55 0.60

Tanδ

Temperature (°C)

Figure S2. Loss tangent vs. temperature plots of DMTA sweeps of polymer/cellulose whisker

nanocomposite films comprising 11.4-11.8% v/v of cellulose whiskers and PVAc/PBMA at a ratio of 60/40 (U), 40/60 (

○

^{), 20/80 (}

□

) swollen with ACSF (after immersion at 37°C for 1 week).

Figure S3. Loss tangent vs. temperature plots of DMTA sweeps of polymer/cellulose whisker nanocomposite films comprising 11.6%v/v of cellulose whiskers and PVAc/PBMA at a ratio of 40/60:

Dry nanocomposite showing a single peak (solid line) the same nanocomposite when swollen in ACSF at 37°C for 1 week and re-dried showing two distinct peaks (dashed line).

20 40 60 80 100

0.1 0.2 0.3 0.4 0.5

Tan δ

Temperature (°C)

4

30 40 50 60 70 80

10⁷ 10⁸ 10⁹

dry 1 dry2

swollen and redried 1 swollen and redried 2

E' (MPa)

Temperature(°C)

Figure S4. DMA temperature sweeps of 23.4%v/v PBMA/cellulose whisker nanocomposite films showing the reversibility of the stiff -soft transition. The materials were tested in the dry state and after subjecting them to a cycle of exposure to water at 65°C for 1 week and then re-drying at 65°C for 48 h.

0 50 100 150 200 250

-1.0 -0.8 -0.6 -0.4

228.9°C

Heat Flow (mW)

Temperature (°C)

PBMA23.4% TW swollen and redried PBMA 23..4% TW

1.915 J/g

229.1°C 4.814 J/g

Figure S5. DSC thermograms of 23.4% v/v PBMA/cellulose whisker nanocomposite films showing the reversibility of the stiff - soft transition. The sample was tested in the dry state (dashed) and after subjecting it to a cycle of exposure to water at 65°C for 1 week and re-drying at 65°C for 48 h (solid).