Contents Abstract………………………………………………………………………………………………………………………………………………………I Acknowledgements………………………………………………………………………………………………………………………………IX Contents……………………………………………………………………………………………………………………………………………………XI List of Figures…………………………………………………………………………………………………………………………………XV List of Schemes…………………………………………………………………………………………………………………………XXXII List of Tables…………………………………………………………………………………………………………………………XXXIII List of Abbreviations…………………………………………………………………………………………………………XXXIV Chapter 1 Introduction 1.1 Supramolecular Self-assembly………………………………………………………………………………………1 1.2 Block Copolymers (BCPs) Self-assembly………………………………………………………………5 1.3 Chain Conformational Effect on Block Copolymer Self-assembly…8 1.3.1 Conformational asymmetry effect on BCP Self-assembly…………………8 1.3.2 Rod-coil Block Copolymer Self-assembly………………………………………………………9 1.3.3 Persistence Length Effect on BCP Self-assembly………………………………12 1.4 Chirality Effects on Self-assembly……………………………………………………………14 1.4.1 Self-assembly of Chiral Superstructures…………………………………………………14 1.4.2 Chiral Block Copolymers (BCPs*) Self-assembly…………………………………16 1.4.2.1 Homochiral Evolution from Chiral Molecular to Chiral Chain Conformation…………………………………………………………………………………………………………………………………………18 1.4.2.2 Homochiral Evolution from Chiral Chain Conformation to Helical Phase………………………………………………………………………………………………………………………………………21 1.4.2.3 Universal Behaviors of BCPs* Self-assembly……………………………………22 1.5 Mechanism for the formation of Chiral Phase……………………………………………27 1.5.1 Experimental Study on the Origin of Twisting and Shifting…27 1.5.2 Theories of Tilt Chiral Lipid Bilayers……………………………………………………31 1.5.3 Orientational Self Consistent Field Theory…………………………………………32 1.6. Controlled BCPs* self-assembly……………………………………………………………………………36 1.6.1 BCPs* Phase Transition Kinetics………………………………………………………………………36 1.6.2 BCP* Phase Transition by Blending of Homopolymer…………………………38 1.7. Application of Block Copolymer (BCP) Chiral Phase on Chiroptical Applications…………………………………………………………………………………………………………41 1.7.1 Luminescence Enhancement by Morphological Evolution…………………41 1.7.2 Surface Plasmonic with Chiral Geometry……………………………………………………43 1.7.3 Optical Chiral Metamaterials………………………………………………………………………………47 Chapter 2 Objectives……………………………………………………………………………………………………………………51 Chapter 3 Experimental Section…………………………………………………………………………………………57 3.1 Materials………………………………………………………………………………………………………………………………………57 3.1.1 Synthesis and Characterization of PS-PLLA BCPs* with High Volume Fraction of PLLA……………………………………………………………………………………………………………57 3.1.2 Synthesis of Low Molecular Weight Polylactide Homopolymer …………………………………………………………………………………………………………………………………………………………………………62 3.1.3 Synthesis of PS-PLLA BCP* with Thiol Junction…………………………………63 3.1.4 Synthesis of Polypeptoid…………………………………………………………………………………………65 3.2 Preparation of Bulk Sample…………………………………………………………………………………………68 3.3 Characterization and Instrumentation………………………………………………………………69 3.3.1 Differential Scanning Calorimetry (DSC)…………………………………………………69 3.3.2 Wide-angle X-ray Diffraction (WXRD)……………………………………………………………69 3.3.3 Small-angle X-ray Scattering (SAXS)……………………………………………………………69 3.3.4 Field-Emission Scanning Electron Microscopy (FESEM)…………………70 3.3.5 Transmission Electron Microscopy (TEM)……………………………………………………70 3.3.6 Electron Tomography (3D-TEM)………………………………………………………………………………71 3.3.7 Electronic Circular Dichroism Spectroscopy (ECD)…………………………71 3.3.8 Vibrational Circular Dichroism (VCD)…………………………………………………………72 3.3.9 Polarizing Light Microscopic (PLM)………………………………………………………………72 Chapter 4 Results and Discussion 4.1 Amplification of Vibrational Circular Dichroism for Chiral Block Copolymers Driven by Self-Assembly………………………………………………………………73 4.1.1 Controlled Self-assembly of PS-PLLA and PS-PLLA/PLLA Blends…………………………………………………………………………………………………………………………………………………………75 4.1.2 Molecular Chirality and Conformational Chirality in Synthe- sized PS-PLLA and PS-PLLA/PLLA Blends………………………………………………………………………79 4.1.3 Vibrational Circular Dichroism in Self-Assembled BCP* Phase……………………………………………………………………………………………………………………………………………………………84 4.1.4 Self-Assembled Phase with Inter-chain Chiral Interactions…………………………………………………………………………………………………………………………………………88 4.2 Phase Behaviors of Chiral Block Copolymers………………………………………93 4.2.1 Phase Behaviors of PS-rich PS-PLLA…………………………………………………………….97 4.2.2 Phase Behaviors of PLLA-rich PS-PLLA………………………………………………………100 4.2.3 Enlargement of H* Forming Window…………………………………………………………………107 4.2.4 Lamellar Undulation……………………………………………………………………………………………………116 4.2.5 Comprehensive Phase Behaviors for Chiral Block Copolymer Self-assembly……………………………………………………………………………………………………………………………………122 4.3 Spiral Hierarchical Superstructures from Twisted Ribbons of Self-Assembled Chiral Block Copolymers………………………………………………………………128 4.3.1 Phase Behaviors of PLLA-rich PS-PLLA with Control Self-assembly…………………………………………………………………………………………………………………………………………………130 4.3.2 Hypothetical Mechanism for Formation of Multilayer lamellae……………………………………………………………………………………………………………………………………………….145 4.2.3 Homochiral Evolution on Chiral Segment-Rich Self-assemble Superstructures………………………………………………………………………………………………………………………………150 4.4 Helical Conformation of High Persistence Length Polymer…160 4.4.1 Molecular and Conformational Chirality of Side-Chain Chiral Peptoid……………………………………………………………………………………………………………………………………………………163 4.4.2 Effects on Peptoid Helical Conformation………………………………………………171 4.5 Helix-arranged Au nanoparticles…………………………………………………………………………175 Chapter 5 Conclusion…………………………………………………………………………………………………………………179 Chapter 6 References…………………………………………………………………………………………………………………183 Publications………………………………………………………………………………………………………………………………………197 List of Figures Figure 1.1. (A) Aggregation occurs when there is a net attraction and an equilibrium separation between the components. The equilibrium separation normally represents a balance between attraction and repulsion. These two interactions are fixed in molecular self-assembly but can be engineered independently in macroscopic self-assembly. (B) and (C) Schematic illustration of the essential differences between irreversible aggregation and ordered self-assembly. (B) Components (shown in blue) that interact with one another irreversibly form disordered glasses (shown in green). (C) Components that can equilibrate, or adjust their positions once in contact, can form ordered crystals if the ordered form is the lowest-energy form (shown in red). (D) Biology provides many examples of self-assembly (here, the formation of a protein, an asymmetric, catalytically active nanostructure); these examples will stimulate the design of biomimetic processes………………………………………………………………………………………………………………………………………………………………2 Figure 1.2. Examples of static self-assembly. (A) Crystal structure of a ribosome. (B) Self-assembled peptideamphiphile nanofibers. (C) An array of millimeter sized polymeric plates. (D) Thin film of a nematic liquid crystal. (E) Micrometersized metallic polyhedra folded. (F) A three-dimensional aggregate of micrometer plates………………………………………………………3 Figure 1.3. Levels of a protein structure. (A) The amino-acid sequence of a protein (primary structure) contains all the information needed to specify (B) the regular repeating patterns of hydrogen-bonded backbone conformations (secondary structure) such as alpha helices (red) and beta sheets (blue). As well as the (C) the way these elements pack together to form the overall fold of the protein (tertiary structure). (D) The relative arrangement of two or more individual polypeptide chains is called quaternary structure.……………………………………………………………………………………………………………………………………………………………4 Figure 1.4. Four ordered morphologies for diblock copolymer melts, spheres (S), cylinders (C), gyroid (G), and lamellae (L), are controlled by the composition fA and the product of the segment–segment interaction parameter and degree of polymerization χN……………………6 Figure 1.5. Phase diagram of PS310-PAA52 in dioxane plus water; the full ternary phase diagram with separate water, dioxane, and copolymer axes looks similar. The colored regions between sphere and rod phases and between rod and vesicle phases correspond to coexistence regions…7 Figure 1.6. Influence of compositional and conformational asymmetry on the spontaneous interfacial curvature for a diblock copolymer during microphase separation. The effects are illustrated by using BCP with (a) symmetric conformation with asymmetric composition, (b) asymmetric conformation with symmetric composition, and (c) asymmetric conformation with asymmetric composition…………………………………………………………………………10 Figure 1.7. Mean-field phase diagrams for diblock copolymer melts for a series of conformational asymmetries. The ordered phases are labeled as lamellar (L), gyroid (G), cylinder (C), sphere (S) and close-packed sphere (Scp). The dots denote mean-field critical points, and the dashed curves are extrapolated phase boundaries………………………………………………………11 Figure 1.8. Phase diagram for rod-coil block copolymers in (a) the weak segregation limit and (b) the moderately segregated region……………12 Figure 1.9. (a) Unstructured chain composed of a racemic mix of side group. (b) Incorporating bulky side groups with identical R-chiralities into the polypeptoid induces a helix. (c) Schematic depicting packing of PnBA-b-polypeptoid into hexagonally packed cylinders with varying helical versus unstructured polypeptoid components………………………………………………………………………………………………………………………………………………………13 Figure 1.10. (a) Chemical structures of 2Cn-Glu-CmN+ amphiphiles and (b) self-assembled chiral superstructures micrographs. (c) Chemical structure of the sugar-appended Schiff base chiral rodcoil amphiphiles and (d) self-assembled chiral superstructures examined by FESEM (left) and TEM (right) micrographs of compounds LC11……………………………………………………………15 Figure 1.11. (a) TEM micrographs of self-assembled H*L (b) 1D SAXS profiles of self-assembled H*L (c) Schematic of PS-PLLA self-assembled H*L in which the helical microdomains are packed in a hexagonal lattice with an interdigitated character (d) Phase diagram of the PS−PLLA BCPs* with respect to χN and composition………………………………………………….17 Figure 1.12. ECD and corresponding UV-Vis absorption spectra of (a) L- and D- lactide acid monomer and (c) P(L-/D-)LA homopolymer in dilute ACN solution (0.05 wt%). (b) VCD and corresponding FTIR absorption spectra of L- and D- lactide acid monomer and (d) P(L-/D-)LA homopolymer in dilute DCM solution (2 wt%)……………………………………………………………………19 Figure 1.13. Schematic illustration handedness determination of H* phase by TEM tomography. Left-handed and right-handed helices in (a) 3D space and (b) 2D projection. (c) Left-handed (left side) and right-handed (right side) helical nanostructures reconstructed from PS/SiO2 helical nanohybrids fabricated using templates from PS−PLLA and PS−PDLA, respectively, for templated sol−gel reaction………………………………………22 Figure 1.14. Schematic illustration of the chirality transfer from molecular chirality to conformation chirality and finally hierarchical chirality BCPs* whereas the molecular chirality as examined by electronic circular dichroism (ECD); the conformation chirality is examined by vibrational circular dichroism (VCD); the self-assembled helical phase from BCPs* can be directly visualized by reconstruction image from three-dimensional TEM tomography (3D TEM)………………………………………23 Figure 1.15. Chemical structures of BCPs*: (a) PBnMA-PDCG; (b) PS-PDLA BCPs*. VCD and corresponding FTIR absorption of (c) C=O and (d) C–O–C vibration in chiral PCGs in the solid state after solution casting. (e) Illustration of inter-chain chiral interactions…………………………………………24 Figure 1.16. Schematic illustration of the chirality transfer from molecular chirality to conformation chirality and finally hierarchical chirality BCPs*. The bulkier aromatic rings side group increase intra twisting power and thus gives obvious inter chain chiral interaction during self-assembly.…………………………………………………………………………………………………………………………26 Figure 1.17. TEM microscopy for (a) PS0.63−PLLA0.18−PLA0.19 and (b) PS0.63−PLA0.17−PLLA0.20 with similar composition but difference sequence; (c) PS0.66−PLLA0.11−PLA0.23 and (d) PS0.66−PLLA0.06−PLA0.28 with both chiral chain as the middle block but different chiral chain length; (e) PS0.63−PLA0.14−PLLA0.23 and (f) PS0.63−PLA0.08−PLLA0.29 with achiral chain as the middle block but different chiral chain length. (g) Schematic illustration of the origins of twisting in self-assembled PS−PLLA−PLA and PS−PLA−PLLA BCPs*………………………………………………………………29 Figure 1.18. Schematic illustrations of the (a) wound-ribbon helix and (b) two types of twisted strip helix (c) transition sequence from the vesicle to helical structure. The arrows represent the local tilt direction…………………………………………………………………………………………………………………………………………………………33 Figure 1.19. oSCF solution of equilibrium H* phase morphology of BCP* melts. The AB interface (ϕA = ϕB =0.5 contour) is shown as transparent purple surface, and blue and green surfaces show high-density contours of (chiral) A-block ends and A-B conjugation points. In horizontal sections, profiles of mean chiral segment orientation, t(x), are indicated by red arrows. A unit cell of H* is shown in (a), while (b) highlights the rotation of the domain and cholesteric twist of segments along the backbone of the helical domain…………………………………………………33 Figure 1.20. Minority chiral component and weak segregation oSCF phase diagrams: (a) fixed segregation (χN = 14); (b) fixed chiral strength = 3.6). Along with standard achiral morphologies (L, lamella; C, cylinder; S, sphere; DG, double-gyroid), chirality stabilizes two new morphopogies: H*, helical cylinder, and UL*, undulated lamella (whose chiral block composition profiles are shown in c and d, respectively)…………………………………………………………………………………………………………………………………………………35 Figure 1.21. Illustration of suggested Gibbs free energy versus transition path from H* and HC to DG……………………………………………………………………………………38 Figure 1.22. Illustration of self-assembly mode for (a) pseudo-H aggregates and (b) pseudo-J aggregates and corresponding illumination from the gels…………………………………………………………………………………………………………………………………………………42 Figure 1.23. Schematic illustration of molecular dispositions for the spin-coated PY/CM thin film before solvent annealing and templated PY/CM nanoarrays. Fluorescence spectra of spin-coated PY/CM thin films on glass substrates (b) with; (c) without the deposition of nanoporous PS template before (solid line) and after (dotted line) solvent annealing………………………………………………………………………………………………………………………………………………………….44 Figure 1.24 (a) Scheme for gold nanoparticle double helices. TEM and reconstruction image for (b) left- and (c) right-handed chiral gold nanoparticle double helices. (d) Experimental CD data for left- and right-handed gold nanoparticle double helices. (e) Illustration for Helical ribbon assembly. (f) TEM images point out the effect of the increase of aliphatic tail length on helical pitch and nanoparticle size and shape in a family of single-helical superstructures. (g) CD signal of gold nanoparticle single helices self-assembly from various aliphatic tail length indicating the decrease of chiroptical properties with increase of aliphatic tail length………………………………………………45 Figure 1.25. (a) Model two-turn gold nanohelix showing critical dimensions. (b) Normalized circular dichroism (CD) spectra of left-handed and right-handed helices. Inset: TEM images of grown structures with left (top) and right (bottom) chirality. (c) Oblique-view and (d) top-view of a left-handed helix structure. (e) Transmittance spectra of helical gold at which RCP and LCP refer to right and left-handed circular polarization of the incident light………………………………………………………………47 Figure 1.26. (a) The resonant transverse bands of chiral materials results in a foreseen negative refraction range of frequencies below . (b) Suggested chiral structure for giving negative refractive index. Each cylinder is a Swiss roll structure wound in a helical fashion. Each layer of foil is separated from the next by a distance d, and the total thickness of foil is N layers……………………………………………………………………………………49 Figure 1.27. Structure of the geomatically chiral metamaterials. (a) Schematics of the 4-layered metamaterial’s unit cell and a photograph of part of a bilayered metamaterial sheet. The gammadions in neighboring layers have a relative twist of 15◦. The RCP excites an anti-symmetric current mode at 4.7 GHz (b), while LCP excites a symmetric current mode at 6.2 GHz (c) (blue and red correspond to currents in opposite directions). (d) Schematics of bilayer cross-wire design. The simulated current density distribution for (e) the right circularly polarized EM wave at 6.5 GHz and (f) the left circularly polarized EM wave at 7.5 GHz (red and blue corresponding to largest and smallest values of current density)…………………………………………………………………………50 Figure 3.1. Comparison of GPC curves (for sample of Table 4.3.1) between (a) PS24-PLLA67 and (b) PS-OH. The PS-PLLA is synthesized through ROP using (b) as a macroinitiator……………………………………………………………………61 Figure 3.2. 1H NMR spectrum (500 MHz) of PS24-PLLA67.The measurement was carried out using deuterated chloroform as a solvent at 25 oC……………………………………………………………………………………………………………………………………………………………………………61 Figure 4.1. TEM image for (a) H*L; (b) DG; (c) DD; (d) corresponding 1D SAXS profiles………………………………………………………………………………………………………………………………………76 Figure 4.2. (a) Visualization of DD phase from solution casting of sample C. Reconstructed images of tetrapod building unit for DD phase (b) and tripod building unit for DG phase (c)…………………………………………………………77 Figure 4.3. (a) TEM image for H*R and (b) corresponding 1D SAXS profiles……………………………………………………………………………………………………………………………………………………………78 Figure 4.4. ECD and corresponding UV-vis absorption spectra of (a) PS-PLLA (samples A, B and C) and PS-PDLA sample (sample D) in dilute AcCN solution……………………………………………………………………………………………………………………………………………………………80 Figure 4.5. ECD and corresponding UV-vis absorption spectra of (a) PS-PLLA (samples A, B and C) and PS-PDLA sample (sample D) in the disordered PS-PLLA thin film state, and (b) H*L-, DG-, DD-forming PS-PLLA and H*R-forming PS-PDLA…………………………………………………………………………………………………………81 Figure 4.6. VCD and corresponding FT-IR absorption spectra of PS-PLLA (samples A, B and C) and PS-PDLA sample (sample D) in dilute CH2Cl2 solution………………………………………………………………………………………………………………………………………………………………83 Figure 4.7. VCD and corresponding FT-IR absorption spectra of disordered PS-PLLA thin films samples…………………………………………………………………………………85 Figure 4.8. (a) VCD and corresponding FT-IR absorption spectra of H*L-, DG-, DD-forming PS-PLLA, H*R-forming PS-PDLA and disordered PS-PLLA. (b) The enlarged VCD spectra of (a) for the comparison between DG-, DD-forming and disordered PS-PLLA………………………………………………………………………………85 Figure 4.9. VLD and corresponding FT-IR absorption spectra of ordered PS-PLLA thin films samples…………………………………………………………………………………………………………….87 Figure 4.10. PLM observations of ordered PS-PLLA thin film at the 0o (left) and 90o (right) position for (a) DD; (b) DG; (c) H*…………………………87 Figure 4.11. Illustration of the formation of a variety of phases including H*, DG and DD from the self-assembly of chiral block copolymers with equivalent volume fraction of chiral segment through chirality transfer from conformational to hierarchical chirality………89 Figure 4.12. DG phase constructed by a pair of single chiral gyroid networks with opposite handedness at which the degrees of chirality are different in these two networks, giving the gyroid networks in the DG phase with different degree of chiral sense. The scale bar in the right shows the degree of chirality in color……………………………………………………………90 Figure 4.13. Volume difference between the two interpenetrating networks of DG, and mean segment twist given from DG plotted as a function of chiral strength ………………………………………………………………………………………………………91 Figure 4.14. (a) and (c) show chiral block domains predicted for H* and DG, respectively, from oSCF theory of chiral diblocks. (b) and (d) show maps of the inter-segment twist in the chiral domains, with color bars indicating positive/right-handed (red) and negative/left-handed (blue)…………………………………………………………………………………………………………………………………………………………………92 Figure 4.15. Phase behaviors of the PS-rich PS−PLLA in the weak and intermediate segregation strength regions; described by composition (fPLLAv) as the abscissa and segregation strength (χN) as the ordinate. The data points were reproduced from J. Am. Chem. Soc. 2009, 51, 18533. The temperature of the phase behaviors is at 140 oC……………………………………………………………………………………………………………………………………………………………………………99 Figure 4.16. Synthetic routes of PLLA-rich PS-PLLA using two-step polymerization starting with ATRP of PS-OH followed by ROP of PLLA……………………………………………………………………………………………………………………………………………………………………101 Figure 4.17. Phase behaviors of the PS−PLLA in the intermediate segregation strength region described by composition (fPLLAv) as the abscissa and segregation strength (χN) as the ordinate. The data points for PS-rich PS-PLLA were reproduced from J. Am. Chem. Soc. 2009, 51, 18533. The temperature of the phase behaviors is at 140 oC…………………………………………………………………………………………………………………………………………………………………………103 Figure 4.18. TEM micrographs of PLLA-rich PS-PLLA samples in the intermediate segregation region. All the samples examined were prepared from solution casting with slow evaporation rate followed by thermal treatment as mentioned. The PS microdomains appear dark and PLLA microdomains appear bright due to RuO4 staining……………………………………104 Figure 4.19. SAXS profiles of PLLA-rich PS-PLLA samples in the intermediate segregation region; all the samples examined were prepared from solution casting with slow evaporation rate, followed by thermal treatment as mentioned………………………………………………………………………………………………105 Figure 4.20. Phase behaviors of the PS-rich PS−PLLA in the strong segregation strength region; the phase diagram was described by composition (fPLLAv) as the abscissa and segregation strength (χN) as the ordinate. The temperature of the phase behaviors is at 140 oC…………………………………………………………………………………………………………………………………………………………………………109 Figure 4.21. TEM micrographs for strong-segregated PS-PLLA samples with PLLA volume fraction ranging from 0.3 to 0.53; all the samples examined were prepared from solution casting with slow evaporation rate, followed by thermal treatment as mentioned. The PS microdomains appear dark and PLLA microdomains appear bright due to RuO4 staining…………………………………………………………………………………………………………………………………………………………110 Figure 4.22. SAXS profiles of strong-segregated PS-PLLA samples with PLLA volume fraction ranging from 0.3 to 0.53; all the samples examined were prepared from solution casting with slow evaporation rate, followed by thermal treatment as mentioned. The results reveal the hexagonal packing for self-assembled PS-PLLA in wide range of volume fraction…………………………………………………………………………………………………………………………………………………………112 Figure 4.23. DSC thermograms of strong-segregated PS-PLLA samples. The heating rate is 10 oC/min……………………………………………………………………………………………………………113 Figure 4.24. Illustration for the formation of helical phase with compositional symmetry, at which (a) the conformational asymmetry effect and (b) chirality effects stabilized the formation of H*…………115 Figure 4.25. One-dimensional WAXD profiles of PS-PLLA after (a) solution casting, followed with thermally annealed at (b)140 ℃ for 2hr or (c) 95 ℃ for 2hr…………………………………………………………………………………………………………………118 Figure 4.26. Phase behaviors of the PS-rich PS−PLLA in the strong segregation strength region; the phase diagram is described by composition (fPLLAv) as the abscissa and segregation strength (χN) as the ordinate. The temperature of the phase behaviors is examined at 140 oC…………………………………………………………………………………………………………………………………………………………………119 Figure 4.27. SAXS profiles of strong-segregated PS-PLLA samples with PLLA volume fraction ranging from 0.55 to 0.70 self-assembled from solution casting at slow evaporation rate, revealing the lamellar packing………………………………………………………………...120 Figure 4.28. TEM micrographs for lamellae-forming PLLA-rich PS-PLLA in the strong segregation region with (a) out-phase undulation and (b) in-phase undulation attributed to the effects of (c) conformational asymmetry and (d) chirality on self-assembly…………………………………………………………121 Figure 4.29. Comprehensive phase behaviors of PS−PLLA; the phase diagram is described by composition (fPLLAv) as the abscissa and segregation strength (χN) as the ordinate. The temperature of the phase behaviors is at 140 oC……………………………………………………………………………………………………124 Figure 4.30. 1D WAXD profiles of solution-cast (a) PS10-PLLA24, (b) PS17-PLLA42 and (c) PS24-PLLA67 after thermal annealing at 180 oC followed by rapid cooling at 150 oC min-1 to 0 oC. The WAXD results appear typical amorphous scattering profile, suggesting that there is no PLLA crystallization effect on microphase-separated morphology……………………………………………………………………………………………………………………………………………………133 Figure 4.31. 1D SAXS profiles of self-assembled PS24-PLLA67 from solution casting with solvent evaporation rate of (a) 0.4 ml hr-1; (d) 0.04 ml hr-1; (e) 0.027 ml hr-1. (b) Corresponding TEM micrograph of (a). (c) Enlarged micrograph of tortuous lamellae in (b)…………………………134 Figure 4.32. TEM micrographs of self-assembled PS24-PLLA67 from solution casting with solvent evaporation rate of 0.04 ml hr-1: (a) concentric lamellar and (b) roll-cake textures from curved multilayered lamellae………………………………………………………………………………………………………………………134 Figure 4.33. 1D WAXD profiles of solution-cast PS24-PLLA67 (fPLLAv = 0.70) after thermal annealing at 180 oC followed by rapid cooling at 150 oC min-1 to 0 oC. The solution-cast samples were prepared by solution casting with solvent evaporation rate of (a) 0.4 ml hr-1; (b) 0.04 ml hr-1; (c) 0.027 ml hr-1……………………………………………………………………………………………136 Figure 4.34. FESEM micrographs of hydrolyzed PS24-PLLA67 from solution casting with solution evaporation rate of 0.04 ml hr-1: (a) concentric columnar-like texture and (b) rolling lamellar texture in a spiral fashion of the PS microdomains after removal of the PLLA…………………………137 Figure 4.35. SEM micrographs of nanostructured SiO2 fabricated by templated sol-gel reaction using nanoporous PS as a template prepared by hydrolysis of self-assembled PS24-PLLA67 with concentric lamellar texture (a) and roll-cake texture (b), followed by removal of PS through UV exposure. The insets show the corresponding illustrations of the forming textures…………………………………………………………………………………………………………………138 Figure 4.36. 3D visualization of self-assembled multilayered lamellae of PLLA microdomain with concentric lamellar texture (a) and roll-cake texture (b)…………………………………………………………………………………………………………………………………………………139 Figure 4.37. Low magnification TEM micrograph of self-assembled PS24-PLLA67 from solution casting with solvent evaporation rate of 0.04 ml hr-1 giving curved multilayered lamellae wiht both concentric and roll-cake texture.………………………………………………………………………………………………………………………………140 Figure 4.38. TEM micrographs of self-assembled PS24-PLLA67 from solution casting with solvent evaporation rate of 0.027 ml hr-1: (a) concentric lamellar and (b) roll-cake textures from curved multilayered lamellae………………………………………………………………………………………………………………………141 Figure 4.39. (a)TEM micrograph and (b) SAXS result of self-assembled PS24-PLLA67 from solution casting with extremely slow solvent evaporation rate at 0.0008 ml hr-1. Undulated lamellae with long-range order can be observed by TEM along with the appearance of reflections at high q region at which the d-spacing was approximately 54 nm determined by the primary reflection in the SAXS profile. The inset shows the corresponding illustration of the forming texture…………………142 Figure 4.40. TEM micrographs of self-assembled (a) PS10-PLLA24 and (b) PS17-PLLA42 from solution casting after thermal annealing at 180 oC followed by thermal treatment as mentioned. The PS microdomains appear dark and PLLA microdomains appear bright due to RuO4 staining……………143 Figure 4.41. (a) SAXS profiles of PLLA-rich PS-PLLA with various molecular weights. (b) The plot of calculated interdomain spacing versus molecular weight on the basis of the primary reflection in SAXS………………………………………………………………………………………………………………………………………………………………….143 Figure 4.42. Schematic illustration for semi-flexible rod-coil block copolymer with helical chain as major block (a), resulting in smectic liquid crystal-like bilayer (b), followed by twisting and bending due to chiral cholesteric liquid-crystal-like force field (c) combined with steric hindrance at chiral interface (d) to scroll the twisted ribbon into concentric texture or develop in a spiral fashion to form roll-cake texture (e) through nucleation and growth mechanism for microphase separation………………………………………………………………………………………………………………………146 Figure 4.43. VCD and corresponding FTIR absorption spectra of C-O-C vibrational mode of PLLA-rich PS24-PLLA67 in the (a) DCM solution and (b) solid states. The concentration of solution is 2 wt%………………………………………………………………………………………………………………………………………………………………………148 Figure 4.44. VLD and corresponding FTIR absorption spectra of C-O-C vibrational mode of PLLA-rich PS24-PLLA67 in the (a) DCM solution and (b) solid states. The concentration of solution is 2 wt%………………………………………………………………………………………………………………………………………………………………………149 Figure 4.45. (a) ECD and corresponding UV-vis absorption spectra and (b) VCD and corresponding FT-IR absorption spectra of the solution state PLLA-rich PS-PLLA (black) and PDLA-rich PS-PDLA (red)…………………152 Figure 4.46. (a) ECD and corresponding UV-vis absorption spectra; VCD and corresponding FT-IR absorption spectra of (b) C=O and (c) C–O–C of PLLA-rich PS-PLLA (black) and PDLA-rich PS-PDLA (red) in the solid state…………………………………………………………………………………………………………………………………………………………………154 Figure 4.47. TEM micrographs of (a) concentric lamellar and (b) roll-cake textures from curved multilayered lamellae, and (c) 1D SAXS profiles of of self-assembled PS24-PDLA67 from solution casting with solvent evaporation rate of 0.04 ml hr-1……………………………………………………………………156 Figure 4.48. Illustration the difficulty for handedness determination for curved multilayered lamellae by TEM 2D projection and 3D tomography. The superstructure become superimposable after flattening by microtomy………………………………………………………………………………………………………………………………………………157 Figure 4.49. TEM micrographs of self-assembled (a) PS24-PLLA67 and (b) PS24-PDLA67 at which PS appear dark and PLLA appear bright due to RuO4 staining; FESEM micrographs of hydrolyzed (c) PS24-PLLA67 and (d) PS24-PDLA67 from solution casting with roll-cake texture in a spiral fashion of the PS microdomains after removal of the PLLA…...158 Figure 4.50. Scheme illustration for the prepared sequence-defined peptoid including homochiral ChirRX and ChiraSX, racemic peptoid RacX, and achiral peptoid AchirX, while X is the total number of monomers…………………………………………………………………………………………………………………………………………………………164 Figure 4.51. ECD and corresponding UV−vis absorption spectra of (a) monomeric ChirR1 and ChirS1 (b) ChirR36, ChirS36, Achir36 and Rac36 (c) overlay of chiral polypeptoid in various chin length including R- and S-form Chir1, Chir6 and Chir36 in dilute AcCN solution. The concentration of solution is 0.1wt%…………………………………………………………………………………165 Figure 4.52. ELD and corresponding UV−vis absorption spectra of monomeric ChirR1 and ChirS1, and polypeptoids ChirR36, ChirS36, Achir36 and Rac36. The concentration of solution is 0.1wt%………………………………………………………………………………………………………………………………………………………………167 Figure 4.53. VCD and corresponding FT-IR absorption spectra of (a) ChirR36, ChirS36, Achir36 and Rac36 peptoid polymers and (b) monomeric ChirR1 and ChirS1 in dilute CDCl3 solution. The concentration of solution is 0.2M……………………………………………………………………………………………………………………………………168 Figure 4.54. VLD and corresponding FT-IR absorption spectra of ChirR36, ChirS36, Achir36 and Rac36 peptoid polymers in dilute CDCl3 solution. The concentration of solution is 0.2M…………………………………………………169 Figure 4.55. Illustration for polypeptoids constituting opposite handedness of chiral aromatic side group give identical right-handed chain conformation………………………………………………………………………………………………………………………………170 Figure 4.56. (a) VCD and corresponding FT-IR absorption spectra and (b) SANS profile for ChirR36 in various solvent (the result is provided by Prof. Segalman from UCSB)……………………………………………………………………………172 Figure 4.57. VCD and corresponding FT-IR absorption spectra for ChirR36 at which measurement at 10 oC, 30 oC and 50 oC was processed………………………………………………………………………………………………………………………………………………………173 Figure 4.58. (a) TEM micrographs of self-assembled PS-ss-PLLA and (b) corresponding 1D SAXS profile…………………………………………………………………………………………………176 Figure 4.59. FESEM micrograph of nanoporous PS template from H*-forming PS-PLLA after hydrolysis of the PLLA.…………………………………………………….177 Figure 4.60. TEM images of Au nanoparticles within the BCP* template via templated electroless plating approach with (a) and (b) in different projection angles; (c) is an enlarge image for the Au nanoparticles……………………………………………………………………………………………………………………………………………178 List of Schemes Scheme 1. Synthetic routes of PS-PLLA. Similar synthetic routes are executed with D-lactide and D,L-lactide as monomers for PS-PDLA and PS-PLA, respectively…………………………………………………………………………………………………………………………58 Scheme 2. Synthetic route of polylactide homopolymer……………………………………62 Scheme 3. Synthetic routes of PS-ss-PLLA. Similar synthetic routes are executed with D-lactide and D,L-lactide as monomers for PS-ss-PDLA and PS-ss-PLA, respectively……………………………………………………………………………………………………………………64 Scheme 4. Synthetic routes of side chain chiral peptoid with sequence control by two-step cycle on a solid support……………………………………………………………66 Scheme 5. Repeat units incorporated in polypeptoid sequences including homochiral NRpe or NSpe used to form helical blocks…………………………………………67 Scheme 6. Designed sequence of polypeptoid with chiral, racemic and achiral chain conformations (provided by Prof. Segalman from UCSB)…67 List of Tables Table 4.2.1 Characterization of synthesized PLLA-rich PS-PLLA with PLLA volume fraction ranging from 0.5 to 0.75………………………………………………………102 Table 4.2.2 Characterization of synthesized strong-segregated PLLA-rich PS-PLLA with various volume fraction…………………………………………………………………109 Table 4.3.1. Characterization of synthesized PLLA-rich PS-PLLA samples with various molecular weights…………………………………………………………………………………………….131 Table 4.3.2. Characterization of synthesized PS-PLLA and PS-PDLA BCPs*……………………………………………………………………………………………………………………………………………………………….151