Depression of Microphase-Separated Domain Size of Polyurethanes in Confined Geometry

Kojio, Ken; Uchiba, Yusuke; Mitsui, Yoshitaka; Furukawa, Mutsuhisa; Sasaki, Sono; Matsunaga, Hiroyasu; Okuda, Hiroshi

doi:10.1021/ma0700577

Cited by 18 publications

(16 citation statements)

References 9 publications

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“…Grazing incident small angle X-ray scattering (GISAXS) measurement also revealed quite similar trend. 24 The reason that the size of microphase-separated domain decreases at thicker film thickness for the PU-45 films can be explained as follows. The occupied volume of the hard segment component for PU-45-F is greater than for PU-34-F.…”

Section: Pu-34-fmentioning

confidence: 99%

The Microphase-separated Structure of Polyurethane Bulk and Thin Films

et al. 2009

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The microphase-separated structure of polyurethane bulk and thin films were investigated using atomic force microscopy (AFM). The polyurethane (PUs) were synthesized with poly(oxytetramethylene) glycol (PTMG), 4,4 0 -diphenylmethane diisocyanate (MDI) and 1,4-butanediol (BD) by a prepolymer method. The hard segment contents were 34 and 45 wt %. Polarized optical microscopy (POM) revealed that the 34 wt % PUE is homogeneous at a macroscopic level, while the 45 wt % one is macrophase-separated into two phases. One phase forms spherulites of ca. 2-5 mm in diameter. AFM observation for the 34 wt % PUE showed the microphase-separated structure, consisting of hard segment domains and a soft segment matrix. In contrast, for the 45 wt % PUE, a lot of the hard segment domains were observed in the spherulite region, indicating that spherulites include much amount of hard segment component, in contrast, outside of spherulite exhibited similar structure to that of 34 wt % one. For the PU bulk, the different microphase-separated structure in the inside and outside of spherulite was successfully observed for the first time. Also, the microphase-separated structure of PU films was investigated as a function of the film thickness. The PU films exhibited similar microphase-separated structure. For the thicker film ($200 nm), the interdomain spacing almost corresponded to bulk one. On the other hand, that for the film thickness below 7 nm dramatically decreased. This seems to be simply related to a decreasing space. We obtained the experimental data, which the phase-separated domain size of multiblock copolymer decreased with decreasing film thickness.KEY WORDS: Polyurethane / Microphase-separated Structure / Atomic Force Microscopy / Thin Film / A microphase-separated structure formed in polymers plays a quite important role for their properties, such as electric, adsorption, mechanical properties. To form the microphaseseparated structure in polymers, they need to possess block structures, which are chemically connected each other. It is well-known that the polyurethane elastomers (PUEs), which possess the multiblock structure, show the microphase-separated structure, 1-6 resulting in giving some unique properties, such as mechanical and adhesive properties [6][7][8][9][10][11][12][13][14][15][16] and biocompatibility.17

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Section: Pu-34-fmentioning

confidence: 99%

The Microphase-separated Structure of Polyurethane Bulk and Thin Films

et al. 2009

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“…Furtheremore, grazing incident small-angle scattering measurement gave consistent results. [5] Therefore, we can reasonable to conclude that the microphaseseparareted structure can be formed even on the condition that the thickness is much smaller than the interdomain spacing for bulk, and the interdomain spacing decreases at the ultrathin state. …”

Section: Resultsmentioning

confidence: 86%

“…Detailed descriptions of the experimental procedure are described in earlier publication from this research group. [5] 2.2. Chain and microphase-separated structures Fourier-tranform infrared (FT-IR) spectra were collected using a Biorad FTS-3000 equipped with a mercury-cadmium-telluride detector to investigate the molecular orientation of the hard segment chains in the PU films.…”

Section: Sample Preparationmentioning

confidence: 99%

Chain and mirophase-separated structures of ultrathin polyurethane films

Kojio

Uchiba

Yamamoto

et al. 2009

J. Phys.: Conf. Ser.

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Abstract. Measurements are presented how chain and microphase-separated structures of ultrathin polyurethane (PU) films are controlled by the thickness. The film thickness is varied by a solution concentration for spin coating. The systems are PUs prepared from commercial raw materials. Fourier-transform infrared spectroscopic measurement revealed that the degree of hydrogen bonding among hard segment chains decreased and increased with decreasing film thickness for strong and weak microphase separation systems, respectively. The microphase-separated structure, which is formed from hard segment domains and a surrounding soft segment matrix, were observed by atomic force microscopy. The size of hard segment domains decreased with decreasing film thickness, and possibility of specific orientation of the hard segment chains was exhibited for both systems. These results are due to decreasing space for the formation of the microphase-separated structure.

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“…Also, the triblock structure will restrict the segregation of lower surface free energy components at the film surface, resulting in the formation of the lateral phase separation. 23 So the introduction of the PMMA segments may promote the fluorine segregation onto the surface. Furthermore, the bright area was primarily composed of the PMMA segments and the PHFBMA segments.…”

Section: Microphase Separation Behaviormentioning

confidence: 99%

Surface microphase separation in PDMS‐b‐PMMA‐b‐PHFBMA triblock copolymer films

Lian

Chen

Liu

et al. 2010

J of Applied Polymer Sci

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Well-defined poly(dimethylsiloxane)-blockpoly(methyl methacrylate)-block-poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) (PDMS-b-PMMA-b-PHFBMA) triblock copolymers were synthesized via atom transfer radical polymerization (ATRP). Surface microphase separation in the PDMS-b-PMMA-b-PHFBMA triblock copolymer films was investigated. The microstructure of the block copolymers was investigated by transmission electron microscopy (TEM) and atomic force microscopy (AFM). Surface composition was studied by X-ray photoelectron spectroscopy (XPS). The chemical composition at

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Depression of Microphase-Separated Domain Size of Polyurethanes in Confined Geometry

Cited by 18 publications

References 9 publications

The Microphase-separated Structure of Polyurethane Bulk and Thin Films

The Microphase-separated Structure of Polyurethane Bulk and Thin Films

Chain and mirophase-separated structures of ultrathin polyurethane films

Surface microphase separation in PDMS‐b‐PMMA‐b‐PHFBMA triblock copolymer films

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