S 1 Synthesis and Aqueous Aggregation Properties of Amphiphilic Surface- Block Dendrimers Nathanael R. Luman and Mark W. Grinstaff Departments of Chemistry and Biomedical Engineering, Metcalf Center for Science and Engineering, Boston University, 590 Commonwealth Ave., Boston, MA 02215 mgrin@bu.edu Supporting Information Instrumentation: All solvents were dried and freshly distilled prior to use (DCM and pyridine with CaH, and THF with Na). All chemicals were purchased from Aldrich or Acros as highest purity grade and used without further purification. All reactions were performed under nitrogen atmosphere at room temperature unless specified otherwise. NMR spectra were recorded on a Varian INOVA spectrometer (for 1 H and 13 C NMR, 400 MHz and 100.6 MHz respectively). Fast atom bombardment mass spectra (FAB-MS) were obtained on a JEOL JMS-SX102A spectrometer using a 3-nitrobenzyl alcohol matrix. MALDI-TOF mass spectra were obtained using a PerSpective Biosystems Voyager-DE Biospectrometry Workstation operating in the positive ion mode using 2-(4- hydroxyphenylazo)-benzoic acid (HABA). Elemental analysis was obtained from Atlantic Microlab, Inc. Size exclusion chromatography was performed using THF as the eluent on a Polymer Laboratories PLgel 3 mm MIXED-E column (3 mm bead size) and a Rainin HPLC system (temp = 25 o C; flow rate = 1.0 mL/min). Polystyrene standards (0.93K, 4.45K, and 12K; PDI = 1.03 - 1.05) were used for calibration. Light micrographs were obtained using an Olympus IX70 inverted light microscope. Tensiometic data was