Supporting information Nanotube formation through the continuous one-dimensional fusion of hollow nanocapsules composed of layer-by-layer poly(lactic acd)s stereocomplex films Kenta Kondo, Toshiyuki Kida, Yuji Ogawa, Yuuya Arikawa and Mitsuru Akashi* Department of Applied Chemistry, Graduate School of Engineering, Osaka University 2-1 Yamada-oka, Suita 565-0871, Japan Contents 1. Experimental procedures 2. SEM images of silica particles coated with (PLLA/PDLA) 10 and (PLLA/PDLA) 10 hollow 3. EDX analysis of silica particles coated with (PLLA/PDLA) 10 and (PLLA/PDLA) 10 hollow 4. FT-IR/ATR spectra of silica particles coated with (PLLA/PDLA) 10 and (PLLA/PDLA) 10 hollow 5. Electron diffraction photograph of (PLLA/PDLA) 10 hollow capsules. 6. TEM images of intermediates of morphology transition and finally formed nanotubes. S1
7. Fluorescent microscopic images of (PLLA/PDLA) 20 -coated silica particles encapsulating rhodamine 6G and rhodamine 6G-encapsulated tubes. 8. SEM and TEM images of nanotubes prepared using a silica template with a diameter of 100 nm. 1. Experimental procedures Preparation of hollow capsules. Silica nanoparticles with a diameter of 300 nm (80 mg) were alternately immersed in acetonitrile solutions (5 ml) of PLLA and PDLA (both concentrations were 5 mg ml -1 ) for 15 min at 50 o C under gentle shaking. After each immersion, the silica nanoparticles were rinsed with acetonitrile at 50 o C. The immersion process was continued for ten cycles to afford ten double layers of PLLA and PDLA. The resulting particles were then treated with 2.3% aqueous HF for 12 h at 4 o C to remove the silica cores. Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) Measurement. The morphologies of (PLLA/PDLA) 10 hollow capsules and nanotubes were observed by the TEM and SEM. TEM measurements were performed with a JEOL JEM-1200EX microscope operated at 80 kv. Energy-dispersive X-ray (EDX) analyses were carried out using Genesis-XM2. TEM samples were prepared by depositing a droplet of the water dispersion on a copper grid covered with polyvinylformal films and allowing them to air-dry overnight, and then stained by RuO 4 vapor. SEM measurements were performed with JEOL JSM-6701F microscope operated at 5 kv. SEM samples were prepared by depositing on a polyethylene terephthalate substrate, and then sputtered by OsO 4. 2 S2
2. SEM images of silica particles coated with (PLLA/PDLA) 10 and (PLLA/PDLA) 10 hollow a) b) 100 nm 300 nm 300 nm Figure S1.SEM images of (a) silica particles coated with (PLLA/PDLA) 10 and (b) (PLLA/PDLA) 10 hollow capsules. 3. EDX analysis of silica particles coated with (PLLA/PDLA) 10 and (PLLA/PDLA) 10 hollow a) Counts C O Cu Al Si b) Counts 0 0.5 1.0 1.5 2.0 2.5 C O Cu Al Si 0 0.5 1.0 1.5 2.0 2.5 kev kev Figure S2. TEM-EDX analysis of (a) silica particles coated with (PLLA/PDLA) 10 and (b) (PLLA/PDLA) 10 hollow capsules. S3 3
4. FT-IR/ATR spectra of silica particles coated with (PLLA/PDLA)10 and (PLLA/PDLA)10 hollow PLLA/PDLA νc=o silica particle νsi-o a) Absorbance (a.u.) b) c) d) e) 1800 1600 1400 1200 1800 1600 1400 1200 800 800 Wavenumber / cm-1 Figure S3. FT-IR/ATR spectra of (a) (PLLA/PDLA)10 hollow capsules, (b) silica particles coated with (PLLA/PDLA)10, (c) PLLA, (d) PDLA, and (e) silica particles. 5. Electron diffraction photograph of (PLLA/PDLA)10 hollow capsules. (200) (010) 300 nm Figure S4. TEM image and ED photograph of (PLLA/PDLA)10 hollow capsules. 4 S4
6. TEM images of intermediates of morphology transition and finally formed nanotubes. a) b) 300 nm 300 nm 1 1 µm 1 µm Figure S5. TEM images of (a) intermediates of morphology transition and (b) the finally formed nanotubes composed of lower molecular weights of PLAs (M w PLLA = 5500, M w PDLA = 5800). 7. Fluorescent microscopic images of (PLLA/PDLA) 20 -coated silica particles encapsulating rhodamine 6G and rhodamine 6G-encapsulated tubes. A fluorescent dye (rhodamine 6G with red emission) was encapsulated into the tubes by using rhodamine 6G-entrapped mesoporous silica particles with an average diameter of 2 µm as a template core. The deposition of (PLLA/PDLA) 20 stereocomplex films on the rhodamine 6G-entrapped mesoporous silica particles by the LbL method gave the (PLLA/PDLA) 20 -coated mesoporous silica particles entrapping rhodamine 6G (Figure S6a). The dense deposition of these particles on a PET substrate by a vertical deposition technique and the subsequent removal of silica core gave the rhodamine 6G-encapsulated tubes (Figure S6b). The fluorescent microscopic images of the tubes clearly show that they have a connected porosity inside. Figure S6. Fluorescent microscopic images of (a) (PLLA/PDLA) 20 -coated silica particles encapsulating rhodamine 6G and (b) rhodamine 6G-encapsulated microtubes. S5 5
8. SEM and TEM images of nanotubes prepared using a silica template with a diameter of 100 nm. 2 µm 2 µm 100 nm Figure S7. SEM image of (a) (PLLA/PDLA) 10 -coated silica nanoparticles (a diameter of 100 nm) and (b) (PLLA/PDLA) 10 nanotubes obtained after HF treatment. (c) TEM images of (PLLA/PDLA) 10 nanotubes. S6 6