Control of Optical Hysteresis in Block Copolymer Photonic Gels: A Step Towards Wet Photonic Memory Films

Kim, Eun-Joo; Kang, Changjoon; Baek, Heeyoel; Hwang, Kyu Suk; Kwak, Dongwoo; Lee, Eunkyung; Kang, Youngjong; Thomas, Edwin L.

doi:10.1002/adfm.201000329

Cited by 80 publications

(80 citation statements)

References 50 publications

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“…[34][35][36] The X-ray photoelectron spectroscopy measurement of the functionalized textile indicated that the grafting of the block copolymer on the surface of the textile was achieved via a very small number of 2-vinylpyridine monomer units, and most of the pyridyl groups on P2VP-b-PDMS copolymer remained unchanged during the grafting process, which preserved the pH-responsive property of P2VP (Supplementary Figure S1). CA measurements were first conducted in air to probe the responsive wettability of the functionalized textile surface by using water droplets with different pH (Supplementary Figure S2).…”

Section: Resultsmentioning

confidence: 99%

Smart surfaces with switchable superoleophilicity and superoleophobicity in aqueous media: toward controllable oil/water separation

2012

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Advanced materials with surfaces that have controllable oil wettability when submerged in aqueous media have great potential for various underwater applications. Here we have developed smart surfaces on commonly used materials, including non-woven textiles and polyurethane sponges, which are able to switch between superoleophilicity and superoleophobicity in aqueous media. The smart surfaces are obtained by grafting a block copolymer, comprising blocks of pH-responsive poly(2-vinylpyridine) and oleophilic/hydrophobic polydimethylsiloxane (i.e., P2VP-b-PDMS) on these materials. The P2VP block can alter its wettability and its conformation via protonation and deprotonation in response to the pH of the aqueous media, which provides controllable and switchable access of oil by the PDMS block, resulting in the switchable surface oil wettability in the aqueous media. On the other hand, the high flexibility of the PDMS block facilitates the reversible switching of the surface oil wettability. As a proof of concept, we also demonstrate that materials functionalized with our smart surfaces can be used for highly controllable oil/water separation processes.

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Section: Resultsmentioning

confidence: 99%

Smart surfaces with switchable superoleophilicity and superoleophobicity in aqueous media: toward controllable oil/water separation

2012

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“…43,44 All the AFM measurements were carried out in the same location near the edge of a scratch. The average thickness of the hybrid layer was found to be 30.4 nm at pH 5.5 and 63.4 nm at pH 2.5.…”

Section: Resultsmentioning

confidence: 99%

Mechanism of nanoparticle actuation by responsive polymer brushes: from reconfigurable composite surfaces to plasmonic effects

et al. 2012

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The mechanism of nanoparticle actuation by stimuli-responsive polymer brushes triggered by changes in the solution pH was discovered and investigated in detail in this study. The finding explains the high spectral sensitivity of the composite ultrathin film composed of a poly(2-vinylpyridine) (P2VP) brush that tunes the spacing between two kinds of nanoparticles-gold nanoislands immobilized on a transparent support and gold colloidal particles adsorbed on the brush. The optical response of the film relies on the phenomenon of localized surface plasmon resonances in the noble metal nanoparticles, giving rise to an extinction band in visible spectra, and a plasmon coupling between the particles and the islands that has a strong effect on the band position and intensity. Since the coupling is controlled by the interparticle spacing, the pH-triggered swelling-shrinking transition in the P2VP brush leads to pronounced changes in the transmission spectra of the hybrid film. It was not established in the previous publications how the actuation of gold nanoparticles within a 10-15 nm interparticle distance could result in the 50-60 nm shift in the absorbance maximum in contrast to the model experiments and theoretical estimations of several nanometer shifts. In this work, the extinction band was deconvoluted into four spectrally separated and overlapping contributions that were attributed to different modes of interactions between the particles and the islands. These modes came into existence due to variations in the thickness of the grafted polymeric layer on the profiled surface of the islands. In situ atomic force microscopy measurements allowed us to explore the behavior of the Au particles as the P2VP brush switched between the swollen and collapsed states. In particular, we identified an interesting, previously unanticipated regime when a particle position in a polymer brush was switched between two distinct states: the particle exposed to the surface of the collapsed layer and the particle engulfed by the swollen brush. On average, the characteristic distance between the particles and the islands increased upon the brush swelling. The observed behavior was a result of the anchoring of the particles to polymeric chains that limited the particles' vertical motion range. The experimental findings will be used to design highly sensitive optical nanosensors based on a polymer-brush-modulated interparticle plasmon coupling.

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“…Previously, we have demonstrated that block copolymer lamellar structures are useful for creating tunable photonic crystals. [26][27][28][29][30] For instance, the lamellae assembled from polystyrene-b -quaternized poly(2-vinyl pyridine) (PS-b -QP2VP) exhibited strong refl ective colors when the QP2VP layers were selectively swollen with solvents. In this case, photonic stop bands (PSBs) varied with the extent of swelling, and which can be controlled by crosslinking density and the species of counter-anions pairing with pyridinium groups.…”

Section: Doi: 101002/adma201103767mentioning

confidence: 99%

“…[26][27][28][29] Briefl y, in-plane oriented lamellar fi lms were fi rst prepared by spin casting PS 57 -b -P2VP 57 solution (Number-average molecular weight (M n ) of each block is 57 × 10 3 g/mol and 57 × 10 3 g/mol for PS and P2VP respectively, PDI = 1.08, 6 wt% in propylene glycol monomethyl ether acetate) onto glass followed by annealing the fi lms in chloroform vapor at 50 ° C for 2 days. The thickness of the fi lms was controlled to ∼ 1 μ m. The P2VP blocks were then quaternized using iodomethane in hexane at 50 ° C for 24 hours.…”

Section: Doi: 101002/adma201103767mentioning

confidence: 99%

Photoresponsive Block Copolymer Photonic Gels with Widely Tunable Photosensitivity by Counter‐Ions

Ahn¹,

Kim²,

Hyon³

et al. 2012

Advanced Materials

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Control of Optical Hysteresis in Block Copolymer Photonic Gels: A Step Towards Wet Photonic Memory Films

Cited by 80 publications

References 50 publications

Smart surfaces with switchable superoleophilicity and superoleophobicity in aqueous media: toward controllable oil/water separation

Smart surfaces with switchable superoleophilicity and superoleophobicity in aqueous media: toward controllable oil/water separation

Mechanism of nanoparticle actuation by responsive polymer brushes: from reconfigurable composite surfaces to plasmonic effects

Photoresponsive Block Copolymer Photonic Gels with Widely Tunable Photosensitivity by Counter‐Ions

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