Supplementary Materials for

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1 advances.sciencemag.org/cgi/content/full/3/7/e /dc1 Supplementary Materials for Biomimetic nanocoatings with exceptional mechanical, barrier, and flame-retardant properties from large-scale one-step coassembly Fuchuan Ding, Jingjing Liu, Songshan Zeng, Yan Xia, Kacie M. Wells, Mu-Ping Nieh, Luyi Sun The PDF file includes: Published 19 July 2017, Sci. Adv. 3, e (2017) DOI: /sciadv fig. S1. SEM image of a nacre acquired on a pearl. fig. S2. Dimensions of MMT nanosheets. fig. S3. Characterization of the integrated PVA/MMT nanocoatings. fig. S4. Comparison of mechanical properties of the materials. fig. S5. Surface morphology of the noncoated and coated PU foams. fig. S6. Comparison of horizontal and vertical casting. table S1. Estimated density of the nanocoatings. Legends for movies S1 to S4 References (56 60) Other Supplementary Material for this manuscript includes the following: (available at advances.sciencemag.org/cgi/content/full/3/7/e /dc1) movie S1 (.avi format). Vertical combustibility testing of the noncoated PET film. movie S2 (.avi format). Vertical combustibility testing of the coated PET film. movie S3 (.avi format). Horizontal combustibility testing of the noncoated PU foam. movie S4 (.avi format). Horizontal combustibility testing of the coated PU foam.

2 fig. S1. SEM image of a nacre acquired on a pearl. The pearl was obtained from Guangzhou, China. It was carefully fractured and sputter coated prior to SEM imaging Average: 260 nm Standard deviation: 60 nm (B) Fraction Lateral dimension (nm) fig. S2. Dimensions of MMT nanosheets. (A) TEM images and (B) lateral dimension distribution of the exfoliated MMT single layer nanosheets, which was determined by Nano Measurer (version 1.2).

3 MMT PVA PVA-C PVA/MMT-50-N Lattice H 2 O C-C O-H (PVA) C-H (PVA) C-H (GA) C=O (GA) C=O (PVA) Transmittance C-O-C Si-O-C C-OH Si-O Al-O-C Al-O Mg-O PVA/MMT-50-C Wavenumber (cm -1 ) fig. S3. Characterization of the integrated PVA/MMT nanocoatings. FTIR spectra of MMT, PVA, PVA-C, PVA/MMT-50-N, and PVA/MMT-50-C. The broad bands peaked at and 1095 cm -1 are associated with the stretching O-H from the intermolecular and intramolecular hydrogen bonds and the stretching of C-OH of the hydroxyl group in PVA (38, 56, 57). The vibrational band at ca cm -1 refers to the stretching C H of alkyl groups for PVA, and the peaks at ca cm -1 assign to the stretching C=O from the acetate group in PVA (the PVA used in this project has a degree of hydrolysis of mol%, thus containing acetate groups) (32, 56). The absorption bands of 3630, 1050, 518, and 468 cm -1 found in samples of MMT, PVA/MMT-50 and PVA/MMT-50-C are associated with -OH stretching of the lattice water, Si-O stretching, Al-O stretching, and Mg-O stretching, respectively (32, 58). The peak at 2860 cm 1 from PVA-C and PVA/MMT-50-C is attributed to C-H stretching of aldehyde (38). And the small peak 1650 cm -1 was from the C=O stretching of aldehyde group from mono-functional reaction of GA (38, 56).

4 1000 Tensile strength (MPa) Young's modulus (GPa) Strain (%) PVA PVA-C PVA/MMT-20-C PVA/MMT-30-C PVA/MMT-50 PVA/MMT-50-C Nacre Aluminum Alloy 2014 Stainless steel type 304 fig. S4. Comparison of mechanical properties of the materials. Mechanical properties of the nanocoatings, nacre, aluminum alloy 2014, and stainless steel type 304 are shown in Table 1. The highest reported strength, modulus, and strain data of nacre are adopted for this plot.

5 fig. S5. Surface morphology of the noncoated and coated PU foams. SEM images of the cell wall of the open cell PU foam before (A) and after (B) coating treatment. Before coating, the cell wall was very smooth. After coating, the change in surface roughness of the cell wall can be observed, suggesting the formation of a thin layer of coating on the cell wall surface.

6 (A) zero flow Start of flow End of flow Dried Relative Intensity (B) Vertical Horizontal Films O2 Permeability of coating layer [10-16 cm 3 (STP) cm/cm 2 s Pa] Vertical Horizontal Theta (degrees) fig. S6. Comparison of horizontal and vertical casting. (A) Schematic showing the comparison of nanocoating formation with and without flow induction. (B) XRD patterns of the PLA-PVA/MMT-50-C nanocoating prepared via vertical and horizontal casting. The inset is the O2 permeability of the two nanocoatings.

7 table S1. Estimated density of the nanocoatings. Sample MMT (wt%) MMT (vol%) Density of sample (g/cm 3 ) PVA/MMT PVA/MMT PVA/MMT PVA/MMT PVA/MMT PVA/MMT The volume fraction of MMT (V MMT ) in the nanocoating can be calculated by Equation (1) V MMT = mc ρc mc ρc + m v ρv (1) where mc and mv are the mass fractions of MMT and PVA in the nanocoating, respectively, and ρc and ρv are the densities of MMT and PVA, respectively. The density of the nanocoating ρ can be calculated by Equation (2), in which ρv is 1.27 g/cm 3 (59) and ρc is 2.80 g/cm 3 (60) ρ = mv mc + 1 mv mcρv + 1 ρc (2) Considering only a very low concentration of GA was used to crosslink PVA, and partial PA should also participate in the co-crosslinking of PVA and MMT, the effect of crosslinking on density change was assumed to be minimum and thus can be neglected. Therefore, the density of each non-crosslinked nanocoating and its crosslinked counterpart are estimated to be the same.

8 movie S1. Vertical combustibility testing of the noncoated PET film. movie S2. Vertical combustibility testing of the coated PET film. movie S3. Horizontal combustibility testing of the noncoated PU foam. movie S4. Horizontal combustibility testing of the coated PU foam. The above videos are also available at