Near-surface alignment of polymers in rubbed films

Near-surface alignment of polymers in rubbed films

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ABSTRACT RUBBED polymer films (generally polyimides) are used in flat-panel displays to control the alignment of liquid crystals in contact with the polymer1–8, a phenomenon first discovered by Maugin1 in 1911. Buffing the film with a cloth produces liquid-crystal alignment in the rubbing direction. Several mechanisms have been proposed to explain this effect. The generation of microgrooves or scratches on the polymer surface during rubbing has led to the suggestion that alignment is the result of long-range elastic effects induced by these surface features3–5. Others have suggested that the polymer chains near the surface are aligned during rubbing and that these then serve as templates for liquid-crystal alignment6–13. Other studies 10–l2 have implied that both mechanisms might be operative. Here we present X-ray scattering measurements which show unambiguously that rubbing a polyimide film causes near-surface alignment of the polymer molecules. For a film 200 nm thick, most of the polymer chains within a thin surface region (about 5 nm thick) are aligned in the rubbing direction; for a 6-nm film essentially all of the chains are aligned within 20° of the rubbing direction. This marked orientation of the near-surface chains at temperatures far below the bulk glass transition temperature shows that the mechanical properties of the near-surface region differ significantly from those of the bulk polymer. Access through your institution Buy or subscribe This is a preview of subscription content, access via your institution ACCESS OPTIONS Access through your institution Subscribe to this journal Receive 51 print issues and online access $199.00 per year only $3.90 per issue Learn more Buy this article * Purchase on SpringerLink * Instant access to full article PDF Buy now Prices may be subject to local taxes which are calculated during checkout ADDITIONAL ACCESS OPTIONS: * Log in * Learn about institutional subscriptions * Read our FAQs * Contact customer support SIMILAR CONTENT BEING VIEWED BY OTHERS MOBILITY GRADIENTS YIELD RUBBERY SURFACES ON TOP OF POLYMER GLASSES Article 18 August 2021 MORPHOLOGIES OF POLYMER CHAINS SPUN ONTO SOLID SUBSTRATES Article 25 July 2024 ROLL-TO-PLATE 0.1-SECOND SHEAR-ROLLING PROCESS AT ELEVATED TEMPERATURE FOR HIGHLY ALIGNED NANOPATTERNS Article Open access 18 December 2023 REFERENCES * Mauguin, C. _Bull. Soc. fr. Miner._ 34, 71–76 (1911). Google Scholar  * Depp, S. W. & Howard, W. E. _Scient. Am._ 268, 90–97 (1993). Article  Google Scholar  * Berreman, D. W. _Phys. Rev. Lett._ 28, 1683–1686 (1972); _Molec. Cryst. liq. Cryst._ 23, 215–232 (1973). Article  ADS  CAS  Google Scholar  * Zhu, Y.-M. _et al._ _Appl. Phys. Lett._ 65, 49–51 (1994). Article  ADS  CAS  Google Scholar  * Lee, E. S., Vetter, P., Miyashita, T. & Uchida, T. _Jap. J. appl. Phys._ 32, L1339–L1341 (1993). Article  ADS  CAS  Google Scholar  * Castellano, J.-P. _Molec. Cryst. liq. Cryst._ 294, 33–41 (1983). Article  Google Scholar  * Geary, J. M., Goodby, J. W., Kmetz, A. R. & Patel, J. S. _J. appl. Phys._ 62, 4100–4108 (1987). Article  ADS  CAS  Google Scholar  * van Aerle, N.A.J.M., Barmentlo, M. & Hollering, R. W. _J. appl. Phys._ 74, 3111–3120 (1993). Article  ADS  CAS  Google Scholar  * van Aerle, N.A.J.M. & Tol, A.J.W. _Macromolecules_ 27, 6520–6526 (1994). Article  ADS  CAS  Google Scholar  * Feller, M. B., Chen, W. & Shen, Y. R. _Phys. Rev._ A43, 6778–6792 (1991). Article  ADS  CAS  Google Scholar  * Chen, W., Moses, O. T., Shen, Y. R. & Yang, K. H. _Phys. Rev. Lett._ 68, 1547–1550 (1992). Article  ADS  CAS  Google Scholar  * Zuang, X., Marucci, L. & Shen, Y. R. _Phys. Rev. Lett._ 73, 1513–1516 (1994). Article  ADS  Google Scholar  * Kikuchi, H., Logan, J. A. & Yoon, D. Y. _Mater. Res. Soc. Symp. Proc._ 345, 247–253 (1994). Article  Google Scholar  * Fuoss, P. H. & Brennan, S. _A. Rev. Mater. Sci._ 20, 365–390 (1990). Article  ADS  CAS  Google Scholar  * Factor, B. J., Russell, T. P. & Toney, M. F. _Macromolecules_ 26, 2847–2859 (1993). Article  ADS  CAS  Google Scholar  * Toney, M. F. & Brennan, S. _J. appl. Phys._ 65, 4763–4768 (1989). Article  ADS  CAS  Google Scholar  * Kochi, M., Horigomi, T. & Mita, I. _Recent Advances in Polyimide Science and Technology_ 192–200 (eds Weber, W. D. & Gupta, M. R.) (Soc. Plastic Engineering, Poughkeepsie, NY, 1987). Google Scholar  * Yoon, D. Y., Parrish, W., Depero, L. E. & Ree, M. _Mater. Res. Soc. Symp. Proc._ 227, 387–393 (1991). Article  CAS  Google Scholar  * Brown, H. R. & Russell, T. P. _Science_ (submitted). * Reiter, G. _Europhys. Lett._ 23, 579–584 (1993). Article  ADS  CAS  Google Scholar  * Orts, W. J., van Zanten, J. H., Wu, W. L. & Satija, S. K. _Phys. Rev.Lett._ 71, 87–90 (1993). Article  Google Scholar  * Keddie, J. L., Jones, R. A. L. & Corey, R. A. _Europhys. Lett._ 27, 59–64 (1994). Article  ADS  CAS  Google Scholar  * Bowden, F. P. & Tabor, D. _The Friction and Lubrication of Solids_ Ch. 1 & 2 (Oxford Univ. Press, London, 1950). MATH  Google Scholar  * Toney, M. F. & Wiessler, D. W. _Acta crystallogr._ 49, 624–642 (1993). Article  Google Scholar  Download references AUTHOR INFORMATION Author notes * Hirotsugu Kikuchi Present address: Kyushu University, Fukuoka, Japan * Michael F. Toney, Thomas P. Russell, J. Anthony Logan and Hirotsugu Kikuchi: Almaden Research Center, IBM Research Division, 650 Harry Road, San Jose, California 95120, USA * James M. Sands and Sanat K. Kumar: Department of Materials Science and Engineering, AUTHORS AND AFFILIATIONS * The Pennsylvania State University, University Park, Pennsylvania, 16802, USA Michael F. Toney, Thomas P. Russell, J. Anthony Logan, Hirotsugu Kikuchi, James M. Sands & Sanat K. Kumar Authors * Michael F. Toney View author publications You can also search for this author inPubMed Google Scholar * Thomas P. Russell View author publications You can also search for this author inPubMed Google Scholar * J. Anthony Logan View author publications You can also search for this author inPubMed Google Scholar * Hirotsugu Kikuchi View author publications You can also search for this author inPubMed Google Scholar * James M. Sands View author publications You can also search for this author inPubMed Google Scholar * Sanat K. Kumar View author publications You can also search for this author inPubMed Google Scholar RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Toney, M., Russell, T., Logan, J. _et al._ Near-surface alignment of polymers in rubbed films. _Nature_ 374, 709–711 (1995). https://doi.org/10.1038/374709a0 Download citation * Received: 24 October 1994 * Accepted: 07 March 1995 * Issue Date: 20 April 1995 * DOI: https://doi.org/10.1038/374709a0 SHARE THIS ARTICLE Anyone you share the following link with will be able to read this content: Get shareable link Sorry, a shareable link is not currently available for this article. Copy to clipboard Provided by the Springer Nature SharedIt content-sharing initiative

ABSTRACT RUBBED polymer films (generally polyimides) are used in flat-panel displays to control the alignment of liquid crystals in contact with the polymer1–8, a phenomenon first discovered


by Maugin1 in 1911. Buffing the film with a cloth produces liquid-crystal alignment in the rubbing direction. Several mechanisms have been proposed to explain this effect. The generation of


microgrooves or scratches on the polymer surface during rubbing has led to the suggestion that alignment is the result of long-range elastic effects induced by these surface features3–5.


Others have suggested that the polymer chains near the surface are aligned during rubbing and that these then serve as templates for liquid-crystal alignment6–13. Other studies 10–l2 have


implied that both mechanisms might be operative. Here we present X-ray scattering measurements which show unambiguously that rubbing a polyimide film causes near-surface alignment of the


polymer molecules. For a film 200 nm thick, most of the polymer chains within a thin surface region (about 5 nm thick) are aligned in the rubbing direction; for a 6-nm film essentially all


of the chains are aligned within 20° of the rubbing direction. This marked orientation of the near-surface chains at temperatures far below the bulk glass transition temperature shows that


the mechanical properties of the near-surface region differ significantly from those of the bulk polymer. Access through your institution Buy or subscribe This is a preview of subscription


content, access via your institution ACCESS OPTIONS Access through your institution Subscribe to this journal Receive 51 print issues and online access $199.00 per year only $3.90 per issue


Learn more Buy this article * Purchase on SpringerLink * Instant access to full article PDF Buy now Prices may be subject to local taxes which are calculated during checkout ADDITIONAL


ACCESS OPTIONS: * Log in * Learn about institutional subscriptions * Read our FAQs * Contact customer support SIMILAR CONTENT BEING VIEWED BY OTHERS MOBILITY GRADIENTS YIELD RUBBERY SURFACES


ON TOP OF POLYMER GLASSES Article 18 August 2021 MORPHOLOGIES OF POLYMER CHAINS SPUN ONTO SOLID SUBSTRATES Article 25 July 2024 ROLL-TO-PLATE 0.1-SECOND SHEAR-ROLLING PROCESS AT ELEVATED


TEMPERATURE FOR HIGHLY ALIGNED NANOPATTERNS Article Open access 18 December 2023 REFERENCES * Mauguin, C. _Bull. Soc. fr. Miner._ 34, 71–76 (1911). Google Scholar  * Depp, S. W. &


Howard, W. E. _Scient. Am._ 268, 90–97 (1993). Article  Google Scholar  * Berreman, D. W. _Phys. Rev. Lett._ 28, 1683–1686 (1972); _Molec. Cryst. liq. Cryst._ 23, 215–232 (1973). Article 


ADS  CAS  Google Scholar  * Zhu, Y.-M. _et al._ _Appl. Phys. Lett._ 65, 49–51 (1994). Article  ADS  CAS  Google Scholar  * Lee, E. S., Vetter, P., Miyashita, T. & Uchida, T. _Jap. J.


appl. Phys._ 32, L1339–L1341 (1993). Article  ADS  CAS  Google Scholar  * Castellano, J.-P. _Molec. Cryst. liq. Cryst._ 294, 33–41 (1983). Article  Google Scholar  * Geary, J. M., Goodby, J.


W., Kmetz, A. R. & Patel, J. S. _J. appl. Phys._ 62, 4100–4108 (1987). Article  ADS  CAS  Google Scholar  * van Aerle, N.A.J.M., Barmentlo, M. & Hollering, R. W. _J. appl. Phys._


74, 3111–3120 (1993). Article  ADS  CAS  Google Scholar  * van Aerle, N.A.J.M. & Tol, A.J.W. _Macromolecules_ 27, 6520–6526 (1994). Article  ADS  CAS  Google Scholar  * Feller, M. B.,


Chen, W. & Shen, Y. R. _Phys. Rev._ A43, 6778–6792 (1991). Article  ADS  CAS  Google Scholar  * Chen, W., Moses, O. T., Shen, Y. R. & Yang, K. H. _Phys. Rev. Lett._ 68, 1547–1550


(1992). Article  ADS  CAS  Google Scholar  * Zuang, X., Marucci, L. & Shen, Y. R. _Phys. Rev. Lett._ 73, 1513–1516 (1994). Article  ADS  Google Scholar  * Kikuchi, H., Logan, J. A. &


Yoon, D. Y. _Mater. Res. Soc. Symp. Proc._ 345, 247–253 (1994). Article  Google Scholar  * Fuoss, P. H. & Brennan, S. _A. Rev. Mater. Sci._ 20, 365–390 (1990). Article  ADS  CAS  Google


Scholar  * Factor, B. J., Russell, T. P. & Toney, M. F. _Macromolecules_ 26, 2847–2859 (1993). Article  ADS  CAS  Google Scholar  * Toney, M. F. & Brennan, S. _J. appl. Phys._ 65,


4763–4768 (1989). Article  ADS  CAS  Google Scholar  * Kochi, M., Horigomi, T. & Mita, I. _Recent Advances in Polyimide Science and Technology_ 192–200 (eds Weber, W. D. & Gupta, M.


R.) (Soc. Plastic Engineering, Poughkeepsie, NY, 1987). Google Scholar  * Yoon, D. Y., Parrish, W., Depero, L. E. & Ree, M. _Mater. Res. Soc. Symp. Proc._ 227, 387–393 (1991). Article 


CAS  Google Scholar  * Brown, H. R. & Russell, T. P. _Science_ (submitted). * Reiter, G. _Europhys. Lett._ 23, 579–584 (1993). Article  ADS  CAS  Google Scholar  * Orts, W. J., van


Zanten, J. H., Wu, W. L. & Satija, S. K. _Phys. Rev.Lett._ 71, 87–90 (1993). Article  Google Scholar  * Keddie, J. L., Jones, R. A. L. & Corey, R. A. _Europhys. Lett._ 27, 59–64


(1994). Article  ADS  CAS  Google Scholar  * Bowden, F. P. & Tabor, D. _The Friction and Lubrication of Solids_ Ch. 1 & 2 (Oxford Univ. Press, London, 1950). MATH  Google Scholar  *


Toney, M. F. & Wiessler, D. W. _Acta crystallogr._ 49, 624–642 (1993). Article  Google Scholar  Download references AUTHOR INFORMATION Author notes * Hirotsugu Kikuchi Present address:


Kyushu University, Fukuoka, Japan * Michael F. Toney, Thomas P. Russell, J. Anthony Logan and Hirotsugu Kikuchi: Almaden Research Center, IBM Research Division, 650 Harry Road, San Jose,


California 95120, USA * James M. Sands and Sanat K. Kumar: Department of Materials Science and Engineering, AUTHORS AND AFFILIATIONS * The Pennsylvania State University, University Park,


Pennsylvania, 16802, USA Michael F. Toney, Thomas P. Russell, J. Anthony Logan, Hirotsugu Kikuchi, James M. Sands & Sanat K. Kumar Authors * Michael F. Toney View author publications You


can also search for this author inPubMed Google Scholar * Thomas P. Russell View author publications You can also search for this author inPubMed Google Scholar * J. Anthony Logan View


author publications You can also search for this author inPubMed Google Scholar * Hirotsugu Kikuchi View author publications You can also search for this author inPubMed Google Scholar *


James M. Sands View author publications You can also search for this author inPubMed Google Scholar * Sanat K. Kumar View author publications You can also search for this author inPubMed 


Google Scholar RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Toney, M., Russell, T., Logan, J. _et al._ Near-surface alignment of polymers in rubbed


films. _Nature_ 374, 709–711 (1995). https://doi.org/10.1038/374709a0 Download citation * Received: 24 October 1994 * Accepted: 07 March 1995 * Issue Date: 20 April 1995 * DOI:


https://doi.org/10.1038/374709a0 SHARE THIS ARTICLE Anyone you share the following link with will be able to read this content: Get shareable link Sorry, a shareable link is not currently


available for this article. Copy to clipboard Provided by the Springer Nature SharedIt content-sharing initiative