Title of Invention

A PROCESS FOR MANUFACTURE OF POLYMERIC FILMS WITH ELECTROACTIVE PATTERNS PRINTED ON THEM

Abstract

A process for manufacture of electroactive polymeric films with electroactive patterns printed on them, comprising i) dissolving polymeric film material, in suitable selective solvent namely N-methyl pyrrolidone and making a polymeric film on a selective substrate namely freshly cleaved mica piece, by any selective conventional method namely spin drying, said polymeric film material selected from polyaniline, polypyrole, polythiophene; ii) covering the polymeric film with a sheet metal mask having number of holes or cuts as per the design of the conducting portion required; iii) mounting the masked film in an ion accelerator under high vacuum; iv) generating conducting ions like Cl+, Cu+ by heating an ionic salt selected from sodium chloride sodium bromide, volatile salts of conducting metals selected from copper, silver, gold in the chamber of the ion accelerator and subsequent electron bombardment. v) subjecting the film under the mask to low energy ion implantation in the ion accelerator and sweeping the film area with the beam of ions at room temperature; vi) taking the film after sufficient exposure out of the ion implantation chamber and storing under ambient conditions for use as film with conducting properties as per the design of the mask;

Full Text

FORM 2 THE PATENTS ACT 1970 COMPLETE SPECIFICATION (See Section 10) TITLE A PROCESS FOR MANUFACTURE OF POLYMERIC FILMS WITH ELECTROACTIVE PATTERNS PRINTED ON THEM APPLICANT Tata Institute ot'Fundamental Research, Homi Bhabha Road, Colaba, Mumbai - 400005,Maharashtra India. An aided autonomous institution under the purview of Department of Atomic Energy, Government of India. The following specification particularly describes the nature of the invention and the manner in which it is to be performed.- ORIGINAL 290/MUM/2000 30/3/2000 GRANTED 24-1-2005 This invention relates to electro-active polymeric films obtained using ion implantation technique and process for producing such electro-active polymeric films having printed patterns for desired end uses. Background of Invention Electro-active polymers are getting ever increasing demand for technological applications such as microelectronics, medical diagnostics. The stability and conductivity properties of these materials. advocate their use in different applications such as electrochromic displays, chemical or biochemical sensors, rechargeable batteries, drug releasing system, electromagnetic shielding, conductive adhesives and conducting anticorrosive coatings. However, preparation of long-lasting conducting films of electrical conducting polymers (ECP) has remained as a challenge in spite of extensive efforts. It has been reported by Huang H. S. et. al., J. Am. Chem. Soc, Faraday Trans. I, 1986, 82, 2385, that dopants like HCI in polyaniline (PANT) often evaporate out on heating or with extended periods of exposure to humid atmosphere. Moreover, the conductivity properties are often delimited by lack of homogeneous distribution of dopant in the bulk of the material. This arises from the inherent drawbacks of the methods 'in vogue'. These have been well described in "Handbook of Conducting Polymers" vol. I, (1986) Ed. T J Skothheim , Marcel Dekker Inc. N. Y.; "Conducting Polymers and Plastics" (1989) Ed. J M Margolis, Chapman & Hall, N Y and in "Organic Conductors" (1994) Ed. J P Farges, Marcel Dekker Inc.' New York. Object The basic object of the present invention is to develop a polymeric film having conducting and non-conducting regions, which would be stable/long lasting and have desired conducting properties. Another object is to provide a process for producing such electro-active polymeric film using ion implantation techniques to thereby achieve homogeneity and stability of the dopant in the film for effective and long-lasting application. Summary of the Invention A process for manufacture of electro active polymeric films with electroactive patterns printed on them, comprising: i) dissolving polymeric film material, in suitable selective solvent namely N-methyl pyrolidone and making a polymeric film on a selective substrate namely freshly cleaved mica piece and the like by any selective conventional method namely spin drying, said polymeric film material selected from poly aniline, polypyrole, polythiophene; ii) covering the polymers film with a sheet metal mask having number of holes or cuts as per the design of the conducting portion required. iii) Mounting the masked film in an ion accelerator under high vacuum. iv) Generating conducting ions like CI+, Cu+ by heating an ionic salt selected from sodium chloride, sodium bromide, volatile salts of conducting metals selected from copper, silver, gold in the chamber of the ion accelerator and subsequent electron bombardment. v) Subjecting the film under the mask to low energy ion implantation in the ion accelerator and sweeping the film area with the beam of ions at room temperature. vi) Taking the film after sufficient exposure out of the ion implantation chamber and storing under ambient conditions for use as film with conducting properties as per the design of the mask. Thus the present invention is directed to achieve patterning in preformed electro-active polymeric films using ion implantation technique with improved stability and conductivity, employing ion accelerator in the range 100-600 kV in acceleration potential. Any electro-active polymeric film such as polypyrole, polythiophene can be used and treated by this technique. Ions of elements such as halogens - F+, CI+, B+, I+ & S+conducting metals such as Cu+, Ag+, Au + etc. can be implanted by this technique. These ions are produced in the ion source by heating the votatile of these elements and sub sequent electron bombardment. Printing of different patterns, conducting circuits, and many other applications are possible by using proper mask. Masks can be made of any conducting metal, which is inert like stainless steel. The mask can have holes or cuts as per the design of the counducting portion required. In particular, ion implantation technique of the invention can be used to implant chlorine in the preformed films of polyaniline (PANT), a well known, and well-characterized electro-active polymer. Films of undoped electro-active polymer polyaniline (PANI) have been prepared on freshly cleaved mica using spin-coating technique. These films have been subjected to low energy ion implantation. The morphology of the films have been studied with the help of optical image analyzer. The conductivity has been measured using four-probe method. Chlorine ion implantation has been found to increase conductivity by three orders of magnitude. The films thus modified do not exhibit signs of fatigue. Examples : The invention will now be illustrated with the help of one example. The example is by the way of illustration only and in no way restricts the scope of the invention. Example I Undoped polyaniline was prepared using electrochemical method. Films were prepared by dissolving PANI in N-methyl pyrrolidinone (NMP) and using spin drying method. Pieces of freshly cleaved mica were used as substrates. Ion Implantation was carried out in a 400 kV ion accelerator located in TIFR, Mumbai. The films were cut into pieces of 1 cm X 1 cm and were mounted in the target chamber of the accelerator. The film was covered with a sheet of metal having rectangular holes. Seven films could be mounted in the chamber at a time. The level ofyacuum in the target chamber was maintained at 1.4 x 10 -4 mm at a valuewhich two orders of magnitude lower than the normal one (~ 10 -6 mm or lower) This has been done in order to avoid possible degradation of the organic sample. The films were implanted with ions of 45 kev energy at room temperature with doses in the range 10 12 to 10 15 ions/sq cm over an area of 1cm x 1cm keeping the ion current in the range 0.05 to 0.1 micro amp. The ion beam was swept across this area to yield a uniform implantation profile. Thus, space occupied by rectangular holes in the metalic cover was exposed to ions. Chlorine ions were obtained by heating. sodium chloride. After the exposure the films were removed and examined. i. Sheet resistance was measured using standard four-probe method. Keithley constant current meter and voltmeter were used for the purpose. Pressure contacts were used for the measurements. Care needs to be taken to avoid puncturing of holes in the film while making pressure contacts. ii. UV- visible absorption spectroscopy was done using Shimadzu spectrophotometer UV 2100. The implanted region is transparent whereas the un-implanted regions exhibit strong absorption maximum around 514 ran which are characteristics of PANI. See photographI image of the film clearly indicating difference in the transmission of visible light from the ion implanted and non-implanted regions of the film. The images are taken with color CCD camera interfaced with PC. The microscope is operating in transmission mode having cold light as light source iii. The conductivity in the location of ion implantation (transparent) is three orders of magnitude higher than in the un-implanted opaque region. This observation correlates with the optical absorption characteristics of two regions. iv. Conductivity experiments were repeated by storing the samples under ambient conditions for a month or more. Neither the conductivity values or the morphology of the films showed any change. v. The films heated for 20 minutes at 355 K; conductivity measured at ambient temperatures also showed no change. This example clearly demonstrates that ion implanted and thus modified PANI films of the invention have both, the desired conducting and less conducting alternate . regions as per the desired end uses/application. WE CLAIM : 1. A process for manufacture of electroactive polymeric films with electroactive patterns printed on them, comprising i) dissolving polymeric film material, in suitable selective solvent namely N-methyl pyrrolidone and making a polymeric film on a selective substrate namely freshly cleaved mica piece, by any selective conventional method namely spin drying, said polymeric film material selected from polyaniline, polypyrole, polythiophene; ii) covering the polymeric film with a sheet metal mask having number of holes or cuts as per the design of the conducting portion required; iii) mounting the masked film in an ion accelerator under high vacuum; iv) generating conducting ions like Cl+, Cu+ by heating an ionic salt selected from sodium chloride sodium bromide, volatile salts of conducting metals selected from copper, silver, gold in the chamber of the ion accelerator and subsequent electron bombardment. v) subjecting the film under the mask to low energy ion implantation in the ion accelerator and sweeping the film area with the beam of ions at room temperature; vi) taking the film after sufficient exposure out of the ion implantation chamber and storing under ambient conditions for use as film with conducting properties as per the design of the mask; 2. A process for manufacture of polymeric films with electroactive patterns printed on them as claimed in claim 1 wherein said ion implantation on the polymeric film is done in a 100-600 kV, preferably 400, ion accelerator in atleast 1.4X10-4 mm vacuum. 3. A process for manufacture of electroactive polymeric films with electroactive patterns printed on them as claimed in any of claims 1 - 2 wherein said polymeric film is of undoped polyaniline prepared by electrochemical method, and 1012 - 1015 Cl+ ions per sq.cm. over an area of 1 cm x 1 cm are implanted on it, after covering it under a mask with square holes, under 1.4 x 10-4 mm vacuum, 0.05 to 0.1 micro-amp ion current. 4. A process for manufacture of polymeric films with electroactive patterns printed on them substantially as herein described in the text and in the example. Dated this 18th day of June 2001 Dr. Sanchita Ganguli OF S. MAJUMDAR & CO (Applicant's Agent)

Documents:

290-mum-2000-cancelled pages(24-01-2005).pdf

290-mum-2000-claims(granted)-(24-01-2005).pdf

290-mum-2000-claims(granted)-(24-1-2005).doc

290-mum-2000-correspondence(27-10-2006).pdf

290-mum-2000-correspondence(ipo)-(11-01-2005).pdf

290-mum-2000-drawing(30-03-2000).pdf

290-mum-2000-form 1(30-03-2000).pdf

290-mum-2000-form 19(30-10-2003).pdf

290-mum-2000-form 2(granted)-(24-01-2005).pdf

290-mum-2000-form 2(granted)-(24-1-2005).doc

290-mum-2000-form 3(30-03-2000).pdf

290-mum-2000-form 4(19-06-2001).pdf

290-mum-2000-form 5(19-06-2001).pdf

290-mum-2000-petition under rule 138(18-05-2004).pdf

290-mum-2000-power of attorney(24-01-2005).pdf

290-mum-2000-power of attorney(30-03-2000).pdf

abstract1.jpg