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Since the first discovery of spontaneous emulsification, the process has remained uncontrollable for centuries leading to unstable emulsion droplets with limited uses. Herein, by in situ observatio...

Fabrication of films with plasmonic nanoparticles (NPs) arrays arranged in chiral configurations of prescribed handedness is highly attractive for the design of new functional materials; however, this remains a formidable challenge in nanotechnology. In this study, we demonstrated the controlled arrangements of gold (Au) NPs into helical structures templated by helical pores created in cross-linked block copolymer (BCP) films. d- and l-tartaric acid (TA) were used to direct the self-assembly of achiral poly(1,4-butadiene)-b-poly(ethylene oxide) BCPs into helical cylindrical morphologies with prescribed handedness, i.e., D or L. Helical pores were generated by BCP cross-linking followed by TA extraction. Helical Au NP arrays, subsequently arranged within the helical pores, exhibited the chiral optical response. The helical structures of NPs arrays and the resulting optical handedness were tunable simply by using either D- or L-porous templates. This simple strategy offers a straightforward pathway for the ...

A systematic study was conducted to investigate the morphology transitions that occur in polystyrene-block-poly(ethylene oxide) (PS-b-PEO) bottlebrush block copolymers (BBCP) upon varying PEO volume fraction (fPEO) from 22% to 81%. A series of PS-b-PEO BBCPs with different PEO side chain lengths were prepared using ring-opening metathesis polymerization (ROMP) of PEO–norbornene (PEO-NB) (Mn ∼ 0.75, 2.0, or 5.0 kg/mol) and PS–norbornene (PS-NB) (Mn ∼ 3.5 kg/mol) macromonomers (MM). A map of fPEO versus side chain asymmetry (Mn(PEO-NB)/Mn(PS-NB)) was constructed to describe the BBCP phase behavior. Symmetric and asymmetric lamellar morphologies were observed in the BBCPs over an exceptionally wide range of fPEO from 28% to 72%. At high fPEO, crystallization of PEO was evident. Temperature-controlled SAXS and WAXS revealed the presence of high order reflections arising from phase segregation above the PEO melting point. A microphase transition temperature TMST was observed over a temperature range of 150–180...

We investigate the linear viscoelastic behavior of poly(styrene)-block-poly(ethylene oxide) (PS-b-PEO) AB diblock brush copolymer materials over a range of volume fractions and with side-chain lengths below entanglement molecular weight (PS Mn ∼ 3.5 kg/mol and PEO Mn ∼ 5 kg/mol). The high chain mobility of the brush architecture results in rapid microphase segregation of the brush copolymer segments, which occurred after mild thermal annealing. Master curves of the dynamic moduli were obtained by time–temperature superposition (tTS). The reduced degree of chain entanglements leads to a unique liquid-like rheology similar to that of bottlebrush (BB) homopolymers, even in the microphase-segregated state. The microphase-segregated domains were found to align at exceptionally low strain amplitudes (γ = 0.01) and mild processing temperatures as confirmed by small-angle X-ray scattering (SAXS). Domain/grain orientation occurred readily at strains within the linear viscoelastic regime (LVR) without noticeable ef...

Brush block copolymers (BBCPs) exhibit attractive features for use as templates for functional hybrid nanomaterials including rapid ordering dynamics and access to broad ranges of domain sizes; however, there are relatively few studies of the morphology of the BBCPs as a function of their structural variables and fewer still studies of BBCP composite systems. Here we report the structural diversity and phase behavior of one class of BBCP nanocomposites as a function of the volume fractions of their components and the side chain symmetry of the BBCPs. We conducted a systematic investigation of gold nanoparticle (NP) (∼2 nm) assembly in a series of poly(tert-butyl acrylate)-block-poly(ethylene oxide) (PtBA-b-PEO) BBCPs with a fixed side chain length of PtBA (Mn = 8.2 kg/mol) but with different PEO brush lengths (Mn = 5.0, 2.0, or 0.75 kg/mol) as well as volume fractions (fPEO = 0.200–0.484). The gold NPs are selectively incorporated within the PEO domain via hydrogen bond interactions between the 4-mercapto...

We report the directed assembly of quantum dots (QDs) within well-ordered photonic nanocomposites using a family of (polynorbornene-graft-poly(styrene))-block-(polynorbornene-graft-poly(ethylene oxide)) (PS-b-PEO) brush block copolymers (BBCPs). Cadmium selenide (CdSe) nanoparticles (NPs) modified with 11-mercaptoundecylhydroquinone are selectively incorporated within the PEO domains of the self-assembled BBCPs via strong hydrogen-bonding interactions between the ligands on QDs and PEO brushes of the BBCPs. Well-ordered QD arrays were readily created within a periodic lamellar polymer matrix, or one-dimensional photonic crystal, with a widely tunable lattice spacing ranging from 46.2 to up to 145 nm. The loading concentration of the QDs can be up to 30 wt % (15 vol %) while maintaining a well-ordered lamellar morphology, providing an optical gain material platform for the systematic investigation of optical properties. Strong photoluminescence and third harmonic generation from the well-ordered QD arrays ...

For well-ordered block copolymer (BCP) nanocomposites containing nanoparticles (NPs), the ratio of NP core diameter (dcore) and BCP domain width (L) has been generally limited with dcore/L < 0.3 when NP/BCP interactions are relatively neutral or weak. Here, we systematically investigate the spatial distribution of gold nanoparticles (NP) ranging in size up to 0.8 times that of the target domain width in symmetric polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) using a hydrogen-bonding-mediated (H-bonding) assembly. NPs with core diameters (dcore) 2, 5, 9, and 15 nm are coated with ligands bearing phenol groups as the hydrogen-donating sites for H-bonding including 2-(11-mercaptoundecyl)hydroquinone and thiol-terminated poly(4-hydroxystyrene). These hydroxylated NPs are selectively incorporated into the P2VP block (domain width L = 7–37 nm) over a wide range of volume fractions (ϕ = 3–26 vol %). Particle distributions are biased toward the center of in the P2VP domains when dcore/L is greater than 0.3 and ...