Polymer Brushes for Molecular Transport - Paul Braun Research ...

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patterned with OTS and the initiator SAMs. The polymerization was carried out at room temperature under a nitrogen atmosphere for 30 to 120 min. At the conclusion of the reaction, the Schlenk tubes were disconnected from the nitrogen line and the substrates were rinsed extensively with H2O followed with sonication in EtOH and then H2O. After drying with a nitrogen stream, the samples were stored in a nitrogen dry box. OTS APS PDMS SiO2 remove stamp SiO2 backfill with APS SiO2 BriBuA, DMAP, DCC NIPAAm, CuBr/PMDETA Figure 3.1. Schematic procedure for micropatterning of PNIPAAm brushes on silica substrates. Unpatterned PNIPAAm brushes were prepared following the same procedure as the patterned PNIPAAm samples except that the OTS patterning step was skipped. As a result, PNIPAAm chains were grafted over the entire surface of the silicon substrates. The chemical route of the PNIPAAm brush synthesis is shown in Scheme 3.1. 34 SiO2 SiO2 patterned PNIPAAm brushes surface initiator
Scheme 3.1. SiO2 OH SiO2 O Si 3.2.4 Characterization of the PNIPAAm brush XPS, FT-IR, XRR, ellipsometry, contact angle goniometry, and fluorescence spectroscopy data was collected on unpatterned PNIPAAm brush samples. Specifically, for the fluorescence spectroscopy experiments, an ethanol solution of Prodan (1×10 -4 M) was deposited onto unpatterned PNIPAAm brushes on silicon wafers; after waiting 5 minutes the samples were spin-coated at 900 rpm for 60 seconds. For ellipsometry, the refractive index of the dry PNIPAAm films is assumed to be 1.46 for films less than 50 nm thick. For thicker PNIPAAm films, ellipsometry yields a refractive index of 1.47 to 1.49. For fluorescence microscopy, an ethanol solution of Prodan was deposited onto patterned PNIPAAm brushes grafted on silica cover slips; after 5 minutes the samples were spin-coated at 2000 rpm for 60 seconds. Fluorescence microscopy imaging was carried out immediately. 3.3 Results H2N Si(OEt) 3 (APS) SiO2 O Si NH O CH3 Br CH3 CH 2 CH O C N H CH CH3 CH3 CuBr/PMDETA Characterization of the unpatterned PNIPAAm brushes was performed through XPS, FTIR, XRR, ellipsometry, and contact angle goniometry prior to patterning studies to investigate the fundamental characteristics of the surface initiated polymerization on silica substrates. 35 NH 2 SiO2 O Si O CH3 Br (BriBuA) HO CH3 NH DCC, DMAP O CH3 CH 3 CH2 CH n C O NH H CH3 CH3
Page 1 and 2: POLYMER BRUSHES FOR MOLECULAR TRANS
Page 3 and 4: © 2005 by Huilin Tu. All rights re
Page 5 and 6: ABSTRACT This thesis studies 2-dime
Page 7 and 8: For my family v
Page 9 and 10: from a vision to concrete plans, an
Page 11 and 12: TABLE OF CONTENTS LIST OF ABBREVIAT
Page 13 and 14: 4.3.6.2 FRAP of Prodan in the patte
Page 15 and 16: CHAPTER 1 INTRODUCTION 1.1 Objectiv
Page 17 and 18: fundamentally different from most o
Page 19 and 20: 1.1.2 General experimental approach
Page 21 and 22: 1.2.1 “Grafting to” approach
Page 23 and 24: mechanism at the later stage, and t
Page 25 and 26: laboratory), sometimes rough,[36] a
Page 27 and 28: (a) (b) Figure 1.4. Schematic repre
Page 29 and 30: 31. S.-J. Ahn, W.-K. Lee, S. Zausch
Page 31 and 32: CHAPTER 2 PRODAN DIFFUSION ON SELF-
Page 33 and 34: tested under continuous flow of nit
Page 35 and 36: coverslips. Water contact angle dat
Page 37 and 38: (a) 0 s 10 s 30 s 120 µm 60 s 120
Page 39 and 40: also sometimes observe bright dots
Page 41 and 42: and the dye, and thus recovery due
Page 43 and 44: 2.5 References 1. C. E. Heitzman, P
Page 45 and 46: formed on gold through microcontact
Page 47: organic solvents.) for 30 minutes f
Page 51 and 52: sp 3 hybridized carbon peak confirm
Page 53 and 54: Reflectivity Figure 3.5. X-ray refl
Page 55 and 56: The AFM images of the patterned PNI
Page 57 and 58: 3.3.7 Fluorescence studies 3.3.7.1
Page 59 and 60: FRAP images and corresponding fluor
Page 61 and 62: advancing water contact angles for
Page 63 and 64: ushes was in the range of 446-450 n
Page 65 and 66: of interest to inside, and so the e
Page 67 and 68: observed are rotational diffusion a
Page 69 and 70: 38. D. Hall, J. Torkelson, Macromol
Page 71 and 72: energy-density battery applications
Page 73 and 74: 4.1.3 Oligoethylene glycol containi
Page 75 and 76: was used to test the thickness chan
Page 77 and 78: The samples are sonicated in aceton
Page 79 and 80: ToF SIMS characterization of POEGA
Page 81 and 82: 0 = f where fp and fH2O are volume
Page 83 and 84: T gp temperature over solvent glass
Page 85 and 86: elative humidity), 25% relative hum
Page 87 and 88: (a) 15s 30s 60s 120s Figure 4.8. FR
Page 89 and 90: of 2.5 nm (as measured by AFM on a
Page 91 and 92: 4.3.5.2 Diffusion of Prodan in the
Page 93 and 94: (a) (b) (c) (d) 500 nm 0 25 nm 0 0
Page 95 and 96: Another possibility is that the nak
Page 97 and 98: ToF SIMS, and the physical properti
Page 99 and 100:
26. L. Lavielle, in Polymer Surface
Page 101 and 102:
presence of a flat wall, and (4) mo
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ultrasonication. After two centrifu
Page 105 and 106:
silicone solution holder (GRACE Bio
Page 107 and 108:
5.3.3 Temperature-response of the c
Page 109 and 110:
more frequently within its “cage
Page 111 and 112:
From the trajectories presented in
Page 113 and 114:
described by Equation 5.5. And then
Page 115 and 116:
3. D. Rosenbaum, P. C. Zamora, C. F
Page 117 and 118:
XPS and FTIR confirmed the chemical
Page 119 and 120:
developed in this thesis have intri
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