Dumpling-Like Nanocomplex of Foldable Janus Polymer Sheet and Sphere

Transcription

1 Dumpling-Like Nanocomplex of Foldable Janus Polymer Sheet and Sphere Lei Gao, Ke Zhang, and Yongming Chen* Supporting Information Experimental Section Materials The triblock terpolymer, P2VP 310 -b-ptepm 58 -b-ps 322, was synthesized previously as described in literature [K. Zhang, G. Lei, Y. M. Chen, Polymer 2010, 5, 2809]. Bulk microphase separation of P2VP-b-PTEPM-b-PS and crosslinking PTEPM Layers A solution of triblock terpolymer (50 mg/ml) in THF was spread onto a clean Teflon sheet and the solvent was allowed to evaporate in a container with THF atmosphere at room temperature for several days. The resulting bulk sample (ca. 0.5 mm in thickness) was then dried for 12 h under vacuum at 60 C. Thermal annealing at 115 C for 24 h under argon gave the triblock terpolymer bulk sample with microphase separation. The sample was exposed to a hydrochloric acidic atmosphere for 5 h and then dried under vacuum at 60 C for 12 h to carry out the sol-gel reaction of the PTEPM domains completely. Preparation of Janus sheets and bis-sheets To neutralize the protonated units during crosslinking, the sample was immersed in NaOH water solution (ph=13) for 24 h and then washed with a plenty of water until neutral. Then the sample was dried under vacuum at 60 C for 12 h. Subsequently, the material was dispersed in THF and stirred to get the Janus sheets. The films disappeared and a colloid solution was obtained in around 1 day. The bis-sheets were obtained by dispersing the crosslinked bulk samples directly in acidic water (ph=2). Supporting gold nanoparticles onto bis-sheets After dispersing gelated hybrid bulk sample (5 mg) in acid water solution (ph=2, 2 ml), a water solution of NaAuCl 4 (ca. 1 mg/ml) was added slowly, where the molar ratio between 2VP and NaAuCl 4 was fixed to ca. 1:0.5. When the mixture solution was stirred ca. 24 h, a freshly prepared aqueous solution of sodium borohydride (10 mg/ml) (ca. 0.1 ml) was added dropwise under vigorous stirring. After the addition was finished, the stirring was continued. Characterization Transmission electron microscopy (TEM) images were obtained using a Hitachi H-800 instrument operated at an accelerating voltage of 100 kv. The images were recorded by a digital camera. For the bulk microphase separated structure, the samples were embedded in epoxy and cured at 40 C overnight. Thin sections ( nm) were obtained using Leica Ultracut UCT ultramicrotome and a diamond knife at room temperature. For the sheets and their complexes, the dispersed samples were prepared by dropping the solution onto a carbon-coated copper grid dried at room temperature. SAXS data were collected on a Rigaku RU300 copper rotating anode (λ=1.54 Å) operated at 40 kv and 50 ma. SAXS S1

2 patterns were collected with a pixel CCD detector. Atomic force microscope (AFM) images were obtained by a Nanoscope IIIa (Digital Instrument) in tapping mode with silicon tips. Samples were prepared by spin-casting the dispersed solution on a clean mica surface at a rotary speed of 2000 rpm for 1 min. Complex formation Janus sheets (5 mg/ml in THF, 0.05 ml) were mixed with crosslinked PS spheres (10 mg/ml or 1 mg/ml in THF, ml) under supersonic, in which acid aqueous solution (ph = 2, ml) was added under stirring to form the nanoobject complexes. S2

3 Bulk lamellar structure A P2VP PTEPM PS B Uni-sheet Bis-Sheet P2VP PTEPM Crosslinked PS Scheme S1. Cartoon presentations of (A) bulk lamellar structure of triblock terpolymers and (B) Janus sheet and its dimmer dispersed in different solvents. The colors represent microdomains of different blocks. S3

4 1 A B I E nm 1E q(a -1 ) Figure S1. (A) SAXS curve and (B) TEM image of microtomed of the bulk microphase-separated P2VP 310 -b-ptepm 58 -b-ps 322. No staining with TEM sample. Figure S2. AFM image of the Janus sheets dispersed in THF. S4

5 A B 100 nm Figure S3. TEM images of the preformed gold NPs captured by the bis-sheets in acidic water (ph=2). (A) and (B) images are in different magnification. S5

6 A B 10 µm C 1 µm Figure S4. Toluene emulsion in water stabilized by Janus sheets. (A) Optical microscopy photo of emulsion, grid size=5 µm; (B) SEM image and (C) TEM image of dried droplets. S6

7 Figure S5. Monodispersed PS particles crosslinked by 20 wt% DVB. Diameter: 226 nm. Figure S6. SEM images of complexes of Janus sheets and PS spheres. S7

8 Figure S7. Selected TEM images of the complexes of Janus sheets taking one PS sphere. Dash circle represents the size of PS sphere inside. A B C 200 nm 200 nm 400 nm Figure S8. SEM images of Janus sheets captured (A) four, (B) five and (C) six PS spheres. Dash circle represents the size of PS spheres in complexes. S8

9 A B C 400 nm 400 nm D E F 500 nm 500 nm 500 nm Figure S9. TEM images of selected complexes of sheets with different number guest spheres. S9