1. Supplementary Figures and Legends a b

Transcription

1 doi: /nture Supplementry Figures nd Legends Supplementry Figure 1. Scnning trnsmission electron microgrphs (STEM) of NCC., STEM prepred from fst evportion of dilute NCC suspension shows individul crystllites., STEM of chirl nemtic NCC film prepred y slow evportion of more concentrted smple. Scle r = 500 nm. 1

2 RESEARCH SUPPLEMENTARY INFORMATION Supplementry Figure 2. Trnsmission electron microgrphs (TEM) of chirl nemtic mesoporous silic., Looking down the helicl xis the twisting rod-like morphology oserved y SEM is seen. The pores pper to e in plne with the lyers nd look rndomly oriented due to the chirl nemtic twisting throughout the lyers., In this imge the helicl xis ppers to e in the plne of the imge going from left to right. Two res with in-plne pores re seprted y n re with pores perpendiculr to the plne of the imge. The pores cn e seen to hve firly uniform dimeter of ~5 nm, which is consistent with the pore size clculted from gs dsorption. Scle r = 100 nm. Supplementry Figure 3. Thermogrvimetric nlysis (TGA, 20 ºC min -1 under ir) of n NCC-silic composite nd pure NCC., TGA of n NCC-silic composite film tht ws 30 wt % SiO 2., TGA of pure NCC film shows n lmost identicl decomposition profile to the composite film. 2

3 RESEARCH Supplementry Figure 4. IR spectr of composite nd mesoporous silic films., IR of composite film shows peks chrcteristic of cellulose (rrows)., IR of clcined film shows complete loss of cellulose peks. Supplementry Figure 5. Powder X-ry diffrction (PXRD) ptterns of composite nd mesoporous silic films., PXRD of composite film shows two peks chrcteristic of crystlline cellulose t 2θ 16º nd 24º., PXRD of mesoporous silic fter NCC removl shows only rod pek chrcteristic of morphous silic nd no peks ssocited with the NCC. 3

4 RESEARCH SUPPLEMENTARY INFORMATION Supplementry Figure 6. Scnning electron microgrph (SEM) of n NCC-silic composite film. Scle r = 1 um. Supplementry Figure 7. Brret, Joyner, nd Hlend (BJH) pore size distriution for chirl nemtic mesoporous silic smple S4 clculted from the dsorption rnch of the isotherm. 4

5 RESEARCH Supplementry Figure 8. Circulr dichroism spectr of 4 different colored mesoporous silic films S1 (lue), S2 (green), S3 (yellow), nd S4 (red). The spectr pper cut off since the peks re greter thn 2000 mdeg, which is the mximum detectle signl on the spectropolrimeter tht ws used. Supplementry Figure 9. Circulr dichroism spectr of mesoporous silic film S3 fter soking with wter (solid curve), isopropnol (dshed curve), nd DMSO (dotted curve). 5

6 RESEARCH SUPPLEMENTARY INFORMATION 3. Supplementry Tles Supplementry Tle 1. Comprison of Nitrogen Adsorption Dt for Selected Smples Smple Wt. % NCC in Composite Pore Volume (cm 3 /g) BET Surfce Are (m 2 /g) Silic Precursor Used S TMOS S2 57 Not mesured Not mesured TMOS S3 54 Not mesured Not mesured TMOS S TMOS S TEOS S TEOS Supplementry Tle 2. Clcultion of n vg nd Helicl Pitch (P) Before nd After Clcintion Smple λ mx n vg P Contrction S1 composite 770 nm nm S1 mesoporous 444 nm nm 146 nm S4 composite 986 nm nm S4 mesoporous 688 nm nm 107 nm 4. Supplementry Discussion The verge refrctive index (n vg ) my e clculted from the volume frctions nd refrctive indices of the individul components ccording to the following eqution: n vg = V i n i (1) In principl, vrying the reltive mounts of silic nd cellulose in our composite mterils could ffect λ mx y ltering n vg nd the helicl pitch. However, ecuse the refrctive indices of SiO 2 nd crystlline cellulose re similr (1.46 nd 1.54, respectively), differences in n vg etween the different composite smples re insignificnt. We cn conclude tht the red-shift of λ mx in the composite films with incresing SiO 2 must therefore e cused y n increse in helicl pitch. In supplementry tle 2 we hve clculted P for the composite films S1 nd S4 using n vg = 1.50 for oth smples nd the experimentlly mesured λ mx vlues ccording to the following eqution λ mx = n vg P (2) After removl of cellulose n vg my e clculted using eqution 1 y employing the pore volume mesured from gs dsorption, the density of SiO 2 (2.63 g/cm 3 ), nd refrctive indices n = 1.00 nd n = 1.46 for ir nd SiO 2, respectively. The clculted vlues of n vg nd P for the clcined smples S1 nd S4 re listed in supplementry tle

7 RESEARCH These clcultions indicte tht the oserved lue-shifts in λ mx fter clcintion re cused y oth the chnge in refrctive index nd contrction of the helicl pitch. The clcultions lso show tht the pitch contrction is lrger for S1 compred to S4. Since the S4 composite hs greter mount of SiO 2 compred to S1, it seems plusile tht the thicker silic wlls cuse this smple to e somewht more resistnt to contrction (though more dt would e required to definitively prove this point). 7