Comparison of Friction Characteristics on TN and VA Mode Alignment Films with Friction Force Microscopy

Kwak, Musun; Chung, Hanrok; Kwon, Hyuk-Min; Kim, Jehyun; Han, Dong Keun; Yi, Yoonseon; Lee, Sangmun; Lee, Chulgu; Cha, Sooyoul

doi:10.1587/transele.e92.c.1366

Cited by 1 publication

(2 citation statements)

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“…Shindo et al measured the friction characteristics of the surface of CaSO 4 (001) and confirmed that a curved structure with a ridge-and-valley direction showed increased friction that curves with a smaller direction. 15 In addition, the friction characteristics also showed the same results for the surface of CaCO 3 (10)(11)(12)(13)(14). 16 In conclusion, it can be said that friction is caused by the potential interaction of the probe and surface element, and that it increases with increasing surface roughness [ Fig.…”

Section: Frictional Property By Rubbing Conditionmentioning

confidence: 68%

“…11 However, there was no frictional asymmetry for the VA mode. 12 This can be interpreted as being due to the type of side chains and the influence of density, and in the case of the VA mode, the vertical direction of the polymer molecules create a stable side chain through intermolecular repulsion. However, there was not enough information to interpret the stability of the side chains of VA-mode AF with just the prebake temperature conditions.…”

Section: Introductionmentioning

confidence: 99%

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Frictional properties of VA‐mode alignment‐film surfaces studied by frictional force microscopy

Kwak¹,

Chung²,

Kwon³

et al. 2010

J Soc Info Display

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The surface-friction characteristics of the post-bake temperature were compared to that of the rubbing condition on VA-mode alignment films (AFs) using frictional force microscopy (FFM). The surface roughness and the surface frictional force increased when the temperature was elevated. However, the frictional asymmetry could not be detected by the frictional loop due to the instability of the side-chain molecular arrangement. For the inter-influences of the total friction and surface roughness, the density of the side chain was changed and it was intentionally rubbed for evaluation. The results showed that the total friction was higher when the rubbing was stronger and side-chain density lower, and the surface roughness also increased in the same manner. This can be explained by the potential interaction due to the curved structure of the side-chain surface that establishes the probe that is scanned and the top surface layer. In order to confirm the influence of the pre-tilt angle on the tilt of the side chain, a test cell was produced under the same conditions and evaluated. The results showed that the pre-tilt-angle decreased according to the difference in density of the side chain and strength of rubbing after injecting liquid-crystal (LC). FIGURE 1 -(a) The principle of AFM/FFM. (b), (c) The density of side chain molecular on PI layer surface. Sample 2 has half density of side chain compared with sample 1. The samples of this experiment were artificially applied rubbing condition and the probe scanned along the rubbing direction.

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