Molecular orientation in laser-induced periodic microstructure on polyimide surface

Lu, Qinghua; Wang, Zongguang; Yin, Jie; Zhu, Zhiwei; Hiraoka, Hiroyuki

doi:10.1063/1.125995

Cited by 21 publications

(20 citation statements)

References 11 publications

(5 reference statements)

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“…Raman absorption bands can be assigned to fully cured PI (polyimide) and PAA (polyamic acid) as precursor or end‐groups [25]. Characteristic bands for polyimide are imide I(C=O stretch at 1786 cm −1 ), imide II(C‐N‐C axial vibration stretch at 1395 cm −1 ), imide III(C‐N‐C transverse vibration stretch at 1124 cm −1 ) [26, 27]. Typical D (1340 cm −1 ) and G (1580 cm −1 ) bands, characteristic for crystalline graphitic carbon, are not observed as was done by, for example, Raimondi et al [28] after ion radiation.…”

Section: Resultsmentioning

confidence: 99%

“…The difference of peak shifts indicates that aromatic imide ring and C‐N‐C bonds are much influenced by corona aging under bipolar pulse voltage [30, 31]. because the reason is that the dipole moment of C=O groups in aromatic imide ring tends to vibrate in the direction of the electric field under corona aging, which allows the movement of molecular segments and orientation of the dipole in the direction of the electric vector [27]. When the electric field of bipolar pulse voltage changes its polar, the dipole moment in aromatic imide ring will vibrate in the opposite direction.…”

Section: Resultsmentioning

confidence: 99%

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Do not be deceived by the cunning jailed side branch

Tremmel

2011

Cathet Cardio Intervent

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We balloon, we stent; this is what we do. If there is a narrowing, we open it, and with this act we conjure a sense of relief. The stenosis is gone. Safety has returned, and everything is back to normal. We do this even with years of data telling us that a stenosis may not actually be as tight as it appears [1,2] or that it may not be causing any limitation of flow [3][4][5][6], and we do this knowing that if either is the case, we have likely done nothing to improve the outcome for our patient [7,8]. Still, such information interferes with what we have worked so hard to achieve and have come to expect in interventional cardiology-a picture-perfect result. In an era when final angiograms look so good that you want to show your friends, it takes fortitude and faith to let a lesion lie. But let there be no doubt, lesions do lie-particularly the jailed side branch (SB).To its credit, the jailed SB has been through a lot. It used to be the center of attention, getting T-stented, culotted, crushed, and kissed, but now, we attend to it only provisionally [9,10]. We have learned that the jailed SB, despite its angiographic appearance, is more often than not physiologically unimpeded, and that it will stay that way over time [11,12]. In fact, if wooed by a jailed SB that is not functionally significant, we could do more harm than good, causing vessel dissection that requires stenting, increasing the risk of restenosis and stent thrombosis, and interfering with the integrity of the main branch. For the jailed SB with a functionally significant stenosis (fractional flow reserve, FFR, <0.75), a simple kissing balloon inflation with a relatively small balloon (balloon/artery ratio <1) in the jailed SB is generally all that is needed for a good functional outcome.The basic finding in this month's study by Shin et al. is that when it comes to the significance of a jailed SB nothing and no one agrees with anything or anyone. Quantitative coronary angiography (QCA) core labs have poor agreement among themselves on which stenoses are 75%, and operators have poor agreement among themselves on the % stenosis, while QCA core labs and operators do not agree with each other, and neither is accurate in predicting FFR. In general, operators overestimate the % diameter stenosis and the functional significance of a jailed SB compared with QCA and FFR, respectively. In other words, as we have been shown over and over, the jailed SB is generally not as bad off as it wants us to think.It is interesting to ponder, then, what drives us to treat the jailed SB. It is not simply that we treat because we are inaccurate in our assessment of a lesions clinical severity. In this study, operators often (16.5% of the time) declared they would treat or not treat a jailed SB without regard to whether they thought the existing SB lesion was going to result in inducible myocardial ischemia. Most often (11.9%), it was operators deciding to treat a lesion even though they did not think it would cause inducible ischemia. Such discordance was more common among...

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Do not be deceived by the cunning jailed side branch

Tremmel

2011

Cathet Cardio Intervent

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“…At lower laser fluence, thermal effect is rather weak, and the final orientation order increases with the increase of laser fluences. While at higher fluence, the thermal effect becomes strong and leads to the relaxation of oriented molecules. , The contrary factors of the laser orientation and thermal relaxation result in the above nearly parabola variation of the anisotropic orientation with laser fluence. Accordingly, it is easy to understand that the complex film (PAZO 12 ) with a higher transition and clearing temperature consequentially display higher saturation value of S at larger laser fluence.…”

Section: Resultsmentioning

confidence: 99%

Photosensitive Liquid-Crystalline Supramolecules Self-Assembled from Ionic Liquid Crystal and Polyelectrolyte for Laser-Induced Optical Anisotropy

Xiao

Lü

et al. 2008

Macromolecules

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A new type of thermotropic liquid-crystalline photosensitive supramolecule was fabricated by ionic self-assembly of polyelectrolyte and functional unit azobenzene ionic liquid crystal (azo-ILC). It was found that the thermal and phase behaviors can be modulated by changing of the spacer length (4, 6, or 12 methylene units designated PAZO 4 , PAZO 6 , and PAZO 12 , respectively). Highly ordered liquid-crystalline structure with a lamellar morphology of different d-spacing was observed. The photoinduced orientation of azobenzene groups in thin films of the obtained ionic-bonding supramolecules was studied by polarized UV-vis and FTIR. Under the irradiation of pulsed laser, very effective induction of optical anisotropy with the preferred direction perpendicular to the pulsed polarization was observed. Typically, the maximum in-plane orientation order (S) of -0.93 for PAZO 12 at maximum absorbance was achieved after irradiation and subsequent anneal at its liquid-crystalline temperature. It was found that the maximum S can be increased by increasing the clearing temperature of the photosensitive material. These results may provide guidelines for the design of effective photoinduced anisotropic materials. Furthermore, uniform alignment control of low-molecular-weight liquid crystals on the oriented supramolecular films was achieved.

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“…During laser irradiation, the PI surface could be softened or melted at the region receiving high energy,13 and this could lead to the relaxation of oriented PI chains induced by mechanical rubbing. However, the irradiation of the polarized pulse laser also led to the orientation of PI chains, the direction of which was perpendicular to LIPS 17, 18. Therefore, it was necessary to investigate the molecular orientation in the PI film after laser irradiation.…”

Section: Resultsmentioning

confidence: 99%

Laser‐induced periodic surface structure on a polymer surface: The effect of a prerubbing treatment on the surface structure

Lü

Yin

et al. 2003

J Polym Sci B Polym Phys

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The influence of the mechanical rubbing of a polyimide (PI) film on the laser-induced periodic structure (LIPS) was demonstrated. The periodicity and amplitude of LIPS were greater when the rubbing direction was parallel to the laser polarization direction. The amplitude became small and the periodicity of LIPS did not show an obvious change when the rubbing direction was perpendicular to the laser polarization direction. The effect of the rubbing pretreatment on LIPS was explained on the basis of the wave-guide effect of rubbing-induced microgrooves on LIPS formation. The orientation of PI chains induced by mechanical rubbing was relaxed after laser irradiation, and a new orientation of PI chains was formed during the LIPS formation. When the rubbing direction was perpendicular to the laser polarization direction, the orientation of PI chains remained in the rubbing direction. The laser-irradiated, perpendicularly rubbed PI surface could be used to verify the effects of surface morphologies and intermolecular interactions on liquid-crystal alignment.

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Molecular orientation in laser-induced periodic microstructure on polyimide surface

Cited by 21 publications

References 11 publications

Do not be deceived by the cunning jailed side branch

Do not be deceived by the cunning jailed side branch

Photosensitive Liquid-Crystalline Supramolecules Self-Assembled from Ionic Liquid Crystal and Polyelectrolyte for Laser-Induced Optical Anisotropy

Laser‐induced periodic surface structure on a polymer surface: The effect of a prerubbing treatment on the surface structure

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