FORMATION OF POLYIMIDE FILMS ON THE METALLIC GRIDS AS A MATRIX BY THE LANGMUIR-BLODGETT METHOD

Svetlana Goloudina¹, Vyacheslav Pasyuta¹, Victor Luchinin¹, Iosif Gofman², Valentina Sklizkova², Vladislav Kudryavtsev²

¹St.Petersburg State Electrotechnical University, St.Peterburg,  Russia

²Institute of Macromolecular Compounds, Russian Academy of Sciences, St.Petersburg,  Russia

Langmuir-Blodgett (LB) method is a promising one for forming of ultrathin polyimide (PI) layers with thickness varied from 0.5 to 100-300 nm. Such films exhibit high thermal (up to 560ºС) and mechanical stability.

PI LB films are prepared in two steps. First, the LB films of prepolymers are prepared. Second, PI films are formed as a result of thermal or chemical imidization.

LB films are usually deposited on non-organic solid surface, but sometimes they are deposited on polymeric substrate. The preparation of ultrathin membranes that cover grids compartments by LB method is interesting both for fundamental and practical approaches.

In the present work the PI films on the metal grid where the size of compartment is 40´40 mm were obtained by LB method. The thickness of this film is 70-130 nm. First we deposited 200 monolayers of alkylammonium salt of rigid-chain polyamic acid (PAA) BPDA-oTD with two multichains of tertiary amine on the Ni-grid for electron microscopy. PI films were formed as a result of thermal imidization. To control the thickness of obtained films PAА monolayers were deposited on Si support. The samples of LB film of PAA salt on grids and Si were heated to 200, 250, 300, 350 or 400°C. The thickness of films on Si was measured before and after the heating by ellipsometry method.

We have shown, that calculated thickness of one monolayer of LB film after the heating to 300, 350 or 400°C is 0.70, 0.65 or 0.57 nm, respectively. This data suggest that PI film was formed. The observation of LB film samples deposited on the grids by optical microscopy reveals that PAA salt film covers 95% of grid compartments. After the heating to 300°C 90% of all compartments are still closed. After the heating to 350°C or to 400°C the film is disrupted

Work is executed with the partial support RBRF (project № 02-03-32683)

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2.                              G.A.Polotskaya, V.P.Sklizkova, S.I.Goloudina, V.M.Pasyuta et.al.// 4th International Symposium “Molecular Order and Mobility in Polymer Systems”. St.Petersburg, June 3-7, 2002, p. 125.

Svetlana Goloudina, Vyacheslav Pasyuta, Viktor Luchinin, Iosif Gofman, Valentina Sklizkova, Vladislav Kudryavtsev Formation of polyimide films on the metallic grids as a matrix by the Langmuir-Blodgett method // 5^th International Symposium «Molecular Mobility and Order in Polymer Systems». Saint Petersburg , june 20-24, 2005 . Book of Abstracts, P-188.

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