Polyaniline-Containing Interpolymer Complexes Synthesized in Low

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Polyaniline-Containing Interpolymer Complexes Synthesized in Low-Polar Organic Media Natalya A. Lokshin,† Vladimir G. Sergeyev,*,† Alexander B. Zezin,† Vladimir B. Golubev,† Kalle Levon,*,‡ and Victor A. Kabanov† Polymer Department, Division of Chemistry, Moscow State University, Moscow, 119899 Russia, and Department of Chemistry and Chemical Engineering, Herman F. Mark Polymer Research Institute, Polytechnic University, Brooklyn, New York 11201 Received January 29, 2003. In Final Form: June 3, 2003 Interpolymer complexes containing polyaniline in the form of emeraldine radical-cations matched with poly(styrenesulfonate) or DNA polyanions were prepared via interchange reaction between polyaniline previously protonated with dodecylbenzenesulfonic acid and poly(styrenesulfonate) or DNA complexed with dioctadecyldimethylammonium chloride which proceeds in chloroform solution at ambient temperature. The reaction mechanism and reaction products were established using elemental analysis, UV-vis, IR, and electron spin resonance spectroscopic measurements. DNA complexed with polyaniline retains its double-helical conformation. The synthesized complexes reveal a considerable conductivity.

Introduction Polymer-surfactant complexes (PSC)s consisting of poly(styrenesulfonate) or DNA polyanions neutralized with amphiphilic cations were used in this study as the starting materials and then matched with polyaniline (PANi) as a conducting component. Such complexes formed as a result of ion exchange reaction between ionic surfactants and oppositely charged polyelectrolytes1,2 are synthesized by simple mixing of water solutions of the components. Interaction between ionic surfactants and oppositely charged polyelectrolytes proceeds so that the surfactant ionic headgroups and charged polyion repeating units form salt bonds (ion pairs) while the surfactant hydrophobic tails aggregate to form micellar species turning out to be neutralized by polyions. The process is mainly provided by translational entropy increase due to release of low-molecular counterions.3 Stoichiometric (1: 1) PSCs are not soluble in water and phase separate in the reaction mixture. However, such PSCs thoroughly dried then can be dissolved in low-polar organic solvents (chloroform, heptane, etc.).4 So redissolved PSCs retain their integrity due to the strong electrostatic attraction between polyion units and surfactant ionic heads in lowpermittivity media, while solubility is provided by the affinity of hydrocarbon tails to an organic solvent. Therefore PSC species in such solutions are pictured as “comblike” macromolecules in which surfactant ionic headgroups are ion paired with polyelectrolyte units while hydrocarbon tails are exposed to the solvent.3-6 In particular, it was shown that PSC species formed from * To whom correspondence should be addressed. Kalle Levon: e-mail, [email protected]; fax, 718-260-3125. Vladimir G. Sergeyev: e-mail, [email protected]; fax, 7(095)939-0174. † Moscow State University. ‡ Polytechnic University. (1) Interactions of Surfactants with Polymers and Proteins; Goddard, E. D., Ananthapadmanabhan, K. P., Eds.; CRC Press: Boca Raton, FL, 1993. (2) Goddard, E. D. Colloids Surf. 1986, 19, 255. (3) Bakeev, K. N.; Yang, M. S.; MacKnight, W. J.; Zezin, A. B.; Kabanov, V. A. Macromolecules 1994, 27, 300. (4) Bakeev, K. N.; Yang, M. S.; Zezin, A. B.; Kabanov, V. A.; Lesov, A. V.; Mel’nikov, A. B.; Kolomiets, I. P.; Rjumtsev, E. I.; MacKnight, W. J. Macromolecules 1996, 29, 1320.

poly(N-ethyl-4-vinylpyridinium bromide) and dodecyl sulfate behave in chloroform solution like individual neutral macromolecular coils in a good solvent.3,4 The same is true for the PSC formed from poly(sodium methacrylate) and dioctadecyldimethylammonium (DODA) chloride.7 Recently it was found that a stoichiometric PSC formed from DNA and DODA chloride also dissolves in chloroform.7-9 Importantly, DNA polyanions incorporated into the PSC species retain their double helicity in the solutions. However, in contrast to ordinary polyions they possess compact conformations. Thus either polycations or polyanions can be transferred into low-polar organic solvents in the form of corresponding PSCs. Note that such PSCs are nothing but salts of a polyacid or polybase and a corresponding amphiphilic base or amphiphilic acid. Mixing of water solutions of oppositely charged polyelectrolytes, in particular polyelectrolyte salts, results in cooperative electrostatic coupling of the corresponding polyions to form interpolymer complexes.10 The question is whether such complexes can be prepared by mixing of organic solutions of the PSCs (i.e., polyelectrolytesurfactant salts) containing oppositely charged polyions. Such opportunity would be of no use if both polyelectrolyte components were soluble in water. However, it makes sense if one or both polymeric compounds are waterinsoluble. In particular, this is the case of PANi emeraldine salts representing practically important conducting polymers. One may expect that PANi-containing interpolymer complexes would be of considerable scientific and practical (5) Kabanov, A. V.; Sergeev, V. G.; Foster, M. S.; Kasaikin, V. A.; Levashov, A. V.; Kabanov, V. A. Macromolecules 1995, 28, 3657. (6) Ponomorenko, E. A.; Tirrell, D. A.; MacKnight, W. J. Macromolecules 1996, 29, 8751. (7) Sergeyev, V. G.; Pyshkina, O. A.; Lezov, A. V.; Mel’nikov, A. B.; Ryumtsev, E. I.; Zezin, A. B.; Kabanov, V. A. Langmuir 1999, 15, 4434. (8) Sergeyev, V. G.; Pyshkina, O. A.; Zezin, A. B.; Kabanov, V. A. Polym. Sci. 1997, A39, 139. (9) Sergeyev, V. G.; Mikhailenko, S. V.; Pyshkina, O. A.; Yaminsky, I. V.; Yoshikawa, K. J. Am. Chem. Soc. 1999, 121, 1780-1785. (10) Bixler, H. L.; Michaels, A. S. In Encyclopedia of Polymer Science and Technology; Mark, H. F., Bikales, N. M., Eds.; Interscience: New York, 1969; Vol. 10, p 765.

10.1021/la034158j CCC: $25.00 © 2003 American Chemical Society Published on Web 07/22/2003

Polyaniline Interpolymer Complexes

interest. Therefore some efforts to prepare such complexes have been already made. In particular, it was shown that PANi can be doped by sulfonated polystyrene in Nmethylpyrrolidon/LiCl mixed solvent.11,12 An interesting approach for preparation of PANi-containing interpolymer complexes is the template polymerization of aniline in the presence of polyanions. This method was used for matching of PANi with sulfonated polystyrene.13,14 A DNA-PANi complex was also synthesized by means of aniline template polymerization in homogeneous aqueous solution. In the latter case, the polymerization was enzymatically catalyzed in order to avoid acidic conditions unfavorable for DNA templates.15,16 DNA-PANi complexes are of particular potential interest as compounds that may be selectively sensitive to adsorption of DNA complementary species. In this work, we explored the possibility to prepare PANi-containing interpolymer complexes via an organic solution procedure. Our main goal was to match PANi and DNA also starting in homogeneous conditions, but using originally synthesized commercial PANi as distinct from the above-mentioned template polymerization procedure. PANi can be dissolved in chloroform upon its complexation (protonation) with strong amphiphilic acids such as dodecylbenzenesulfonic acid (DBSA) or 10-camphorsulfonic acid.17 In our study, we used a chloroform solution of PANi-DBSA complex as a polycationic counterpart and the PSCs formed by complexation of poly(styrenesulfonate) (PSS) or DNA as polyanionic counterparts with DODA chloride. These PSCs are also soluble in chloroform. Thus we explored the possibility to match PANi with PSS or DNA via an ion interchange reaction between the PANiDBSA complex and the above PSCs in chloroform solution. In doing so, the PANi -PSS system was considered as a model to establish optimum conditions for the reaction between PANi-DBSA and DNA-DODA complexes. At the same time, the parallel study of both systems served to check the generality of the procedure explored. Embarking on this study, we were encouraged by the recently established fact that DODA chloride added to the chloroform solution of PANi oligomer (trimer) protonated with DBSA displaces DBSA from the complex to form DODA-DBSA salt and hydrogen chloride.18 The latter is not able to protonate the trimer in low-polar solvents. Therefore the trimer emeraldine salt transforms into emeraldine base. The above observation suggests that the PANi-DBSA complex dissolved in chloroform may also participate in ion exchange reactions. Experimental Section Materials. PANi emeraldine base (intrinsic viscosity [η] ) 0.378 dL/g in 95.6% sulfuric acid) was obtained from PANIPOL (Finland) and used without further purification. DBSA and DODA chloride (Tokyo Kasei Kogyo Co.), chloroform, and poly(sodium styrenesulfonate) (Aldrich) were used as purchased. Double(11) Liao, Y.-H.; Levon, K.; Laakso, J.; O ¨ sterholm, J.-E. Macromol. Rapid Commun. 1995, 16, 393-397. (12) Yue, J.; Epstein, A. J.; MacDiarmid, A. G. Mol. Cryst. Liq. Cryst. 1990, 189, 255. (13) Liu, J.; Yang, S. C. J. Chem. Soc., Chem. Commun. 1991, 1529. (14) Angelopoulos, M.; Shaw, J.; Huang, W.; Lecorre, M.; Tissier, M. Polym. Eng. Sci. 1992, 32, 1535. (15) Samuelson, L. A.; Anagnostopoulos, A.; Alva, K. S.; Kumar, J.; Tripathy, S. K Macromolecules 1998, 31, 4376-4378. (16) Nagarajan, R.; Liu, W.; Kumar, J.; Tripathy, S.; Bruno, F. F.; Samuelson, L. A. Macromolecules 2001, 34, 3921-3927. (17) Cao, Y.; Qiu, J.; Smith, P. Synth. Met. 1995, 69, 187-190. (18) Lokshin, N. A.; Pyshkina, O. A.; Golubev, V. B.; Sergeyev, V. G.; Zezin, A. B.; Kabanov, V. A.; Levon, K.; Piankijsakul, S. Macromolecules 2001, 34, 5480-5486.

Langmuir, Vol. 19, No. 18, 2003 7565 stranded DNA, sodium salt, 300-500 base pairs, from salmon sperm was obtained from ICN. Synthesis of Polymer-Surfactant Complexes. The complex of PANi with DBSA was prepared by mixing a chloroform solution of DBSA (0.3 M) with PANi emeraldine base powder suspended in chloroform. The molar ratio of DBSAH to nitrogen atoms of PANi repeating units in the final mixture was 0.75. The reaction mixture was stirred for 48 h at 30 °C and then filtered. A clear green solution of PANi-DBSA was obtained. Complexes of DNA or PSS with DODA were prepared as follows. DNA or PSS sodium salts were dissolved in 0.01 NaCl aqueous solution to get 1.5 × 10-4 M solutions of the polyelectrolytes. Then these solutions were mixed with DODA chloride aqueous solution containing an equimolar amount of the surfactant. The insoluble highly dispersed DNA-DODA or PSSDODA complexes formed were separated from the supernatant by centrifugation at 15 000 rpm and then decanted and held in a vacuum desiccator over CaCl2 to a constant weight (from 7 to 10 days). When placed in chloroform, the dried complex samples dissolved in several hours at room temperature. Characterization. All measurements were carried out at ambient temperature. UV-visible absorption spectra were recorded by the use of a Shimadzu UV 3101PC spectrophotometer with quartz cells (optical path 1 and 0.2 cm). IR spectra of the PSCs and PANi-containing interpolymer complexes were recorded with Specord M-80 using the samples homogenized in KBr pellets. IR spectra of supernatant chloroform solutions were recorded using KBr cells. Elemental analysis was performed by QTI (Quantitative Technologies Inc., NJ). Electron spin resonance (ESR) spectra of the solid samples were recorded with an X-range RE-1307 spectrometer (Japan) using glass ampules with an inner diameter of 2 mm. Samples were vacuumed to the remaining pressure 5.0 × 10-3 mmHg to remove oxygen. Mn2+ in MgO and sugar carbon were used as standards. The concentration of ESR active spins was calculated by the double integrating method. The conductivity measurements were performed by the conventional collinear four-point probe technique using a Keithley 220 current source meter and a Keithley 617 multimeter. The PANiDBSA samples for conductivity measurements were in the form of films cast from chloroform solution on the glass surface. PANiPSS and PANi-DNA complexes were desiccated in a vacuum at ambient temperature for 48 h and then compacted into thin films using a hydraulic press with a standard IR die. Conductivity σ was calculated using the formula derived for thin sheets.19

σ (S/cm) )

ln 2 I πt U

where t is the sample thickness, I is the current, and U is the voltage.

Results and Discussion On addition of the aqueous solution of DODA chloride to the aqueous solutions of DNA or PSS sodium salts, the reaction mixtures were first transparent but then progressively turned turbid at a DODA-to-polyelectrolyte molar ratio, Z, exceeding 0.8 in the case of DNA and 0.1 in the case of PSS due to formation of insoluble PSCs. The concentration of the polyelectrolytes in the supernatant was measured spectrophotometrically after insoluble products were separated. The obtained precipitation curves are shown in Figure 1. It is seen that at Z close to 1 the solutions actually contain no determinable amount of the polyelectrolytes. Elemental analyses (P, N, C, S) revealed that both PSCs were actually stoichiometric. The DNA-DODA and PSS-DODA PSCs as well as the PANi- DBSA complex dissolved in chloroform were studied by UV spectroscopy.7,18,20,21 Importantly, the (19) Electrical and optical polymer systems; Wise, D., Winek, G., Trantolo, D., Cooper, T. M., Gresser, J. D., Eds.; Marcel Dekker: New York, 1998. (20) Pyshkina, O. A.; Sergeyev, V. G.; Zezin, A. B.; Kabanov, V. A. Dokl. Chem. 1996, 348, 138-140.

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Figure 1. Relative absorbances (A/A0) at 263 nm of DNA (a) and sodium PSS (b) in the supernatant after centrifugation (ω ) 15 000 rpm) at various DODA/polyelectrolyte molar ratios (Z) in 0.01 NaCl solution at ambient temperature.

Lokshin et al.

Figure 3. Absorbances for the long-wave band near 790 nm (λmax) of chloroform solutions of the mixtures of PANi-DBSA with PSS-DODA (a) and DNA-DODA (b) vs PE/(aniline unit) molar ratios. Scheme 1

Figure 2. UV-visible spectra of (A) PANi-DBSA (a) and mixtures of PANi-DBSA with PSS-DODA at different PSS/ (aniline unit) molar ratios: 0.1 (b), 0.2 (c), 0.25 (d), and 0.75 (e); (B) PANI-DBSA (a) and mixtures of PANI-DBSA with DNADODA at different DNA base/(aniline unit) molar ratios: 0.15 (b), 0.2 (c), 0.25 (d), 0.5 (e), and 0.75 (f) in chloroform solution.

absorption bands at ca. 370 and 790 nm, characteristic for PANi emeraldine salts, were clearly identified in the range which is optically transparent for DNA-DODA and PSS-DODA PSCs. Mixing of PSS-DODA or DNA-DODA solutions in chloroform with PANi-DBSA chloroform solution results in formation of insoluble green precipitates. The green color indicates that PANi transferred into precipitate remains in emeraldine salt form. Figure 2A,B representing the UV spectra of the supernatants shows that absorbances at 370 and 790 nm characteristic for PANi emeraldine salt in solution decrease and subsequently (21) Pyshkina, O. A.; Sergeyev, V. G.; Lezov, A. V.; Mel’nikov, A. B.; Ryumtsev, E. I.; Zezin, A. B.; Kabanov, V. A. Dokl. Chem. 1996, 349, 207-210.

disappear with increasing the amount of added PSSDODA (A) or DNA-DODA solution (B). Figure 3 shows the absorbance of the supernatant solutions at 790 nm versus the composition of the reaction mixtures. In the case of the PSS-DODA complex, a green precipitate starts to form at a PSS/(aniline unit) molar ratio equal to ca. 0.1. Finally all protonated PANi transfers into insoluble product at a PSS/(aniline unit) molar ratio of ca. 0.7 (curve a) so that supernatant becomes colorless and transparent. In the case of the DNA-DODA complex, the absorbance at 790 nm remains unchanged up to a DNA/(aniline unit) molar ratio of ca. 0.3 (curve b). Green precipitate is formed at further increase of the amount of added DNA-DODA solution. Precipitation is completed at a DNA/(aniline unit) molar ratio of ca. 1.2. At this point, the supernatant becomes colorless and transparent. However, at a higher DNA/(aniline unit) molar ratio complete precipitation does not occur. At a DNA/(aniline unit) molar ratio of ca. 1.5, the precipitate is not formed at all and the resulting product remains dissolved in the reaction mixture (Figure 3, curve b). The mere fact that the two soluble polymer salts (i.e., PSCs) form a precipitate on mixing their solutions at ambient temperature unambiguously means that the polycation and polyanion are coupled to form an insoluble complex due to the ion interchange reaction. The step of such reaction between the PANi-DBSA emeraldine salt and PSS-DODA or DNA-DODA complexes which is apparently driven by an entropy increase caused by release of amphiphilic counterions into environmental chloroform solution may be represented by Scheme 1. The amount of formed (DBSA-•DODA+) salt soluble in chloroform should be equal to the number of PANi imine

Polyaniline Interpolymer Complexes

Langmuir, Vol. 19, No. 18, 2003 7567 Chart 1

Figure 4. IR spectra of PANi-DBSA (a), sodium PSS (b), PANi-PSS (c), PANi (d), DNA (e), and PANi-DNA (f) samples (transmittance in arbitrary units).

radical-cations neutralized by sulfonate or phosphate groups of the corresponding polyelectrolytes. In fact, IR spectra of both supernatant solutions after complete precipitation of the reaction products correspond to a spectrum of the model mixture of DBSA and DODA chloride in chloroform. At the same time, no characteristic peaks of PANi emeraldine salt, PSS, or DNA were observed in supernatant solutions. Formation of a soluble complex on overdosing DNA-DODA complex added to PANiDBSA solution (right part of curve b in Figure 3) is apparently caused by a solubilization effect of excess DNA-DODA fragments incorporated into the complex species at high DNA-DODA concentration. The chemical composition of the insoluble reaction products was assessed qualitatively by IR spectroscopy. Unfortunately PANi-containing compounds similar to other polyconjugated polymers do not give well-resolved IR spectra applicable for quantitative analyses because of strong background absorption of IR radiation. However, IR spectroscopy can be used to identify the characteristic bands of polymeric components in the complex precipitates. The IR spectra of the precipitates compared with those of the initial DNA, PSS, PANi, and PANi-DBSA are shown in Figure 4. The well-expressed stretching Car-N band at 1300 cm-1 indicates the presence of PANi in both complex precipitates (compare curves a and d with curves c and f). The ring stretching vibration band of the quinoid form observed at around 1585 cm-1 in original PANi is shifted to 1568 cm-1 in both PANi-PSS and PANi-DNA precipitates (compare curve d with curves c and f). At the same time, the ring stretching vibration of the benzenoid form appears at around 1490 cm-1 indicating that PANi is actually involved in complexation in the form of emeraldine salt22,23 as shown in Scheme 1. The (22) Furukawa, Y.; Ueda, F.; Hyodo, Y.; Harada, I.; Nakajima, T.; Kawagoe, T. Macromolecules 1988, 21, 1297. (23) Chen, S.-A.; Hwang, G.-W. Polymer 1997, 38, 333.

SO3 group valence vibration bands at 1007-1038 and 1125 cm-1 23 (curve c) may be caused either by PSS or the residual DBSAH also incorporated into the PANi-PSS precipitate. However, the intensive band at 1636 cm-1 observed in the spectra of sodium PSS and PANi-PSS precipitate is not presented in the PANi-DBSA spectrum. The band of the antisymmetric stretching vibration of the PO2- groups at 1240 cm-1 in free DNA (curve e) and in the PANi-DNA precipitate (curve f) overlaps with the BBB stretching band in the PANi spectra. However, absorption at the region of 1750-1550 cm-1 which is assigned to the CdO, CdC, and CdN double bond stretching vibrations in the DNA base pairs24 clearly indicates incorporation of DNA into the complex precipitate. The composition of the complexes was estimated by elemental analysis for N, P, and S. Assuming that the structure of the PANi-PSS complex may be represented by formula A in Scheme 1, one should expect the atomic ratio N/S ) 2. In the experiment, the N/S ratio has been found to be close to 1.2 (N, 3.03 wt %; S, 5.88 wt %) indicating that the residual DBSA molecules are actually incorporated in the PANi-PSS complex most likely because of hydrogen bonding to the neutral imine groups (ca. 6 DBSA per 10 repeating units). The number of nitrogen atoms per one phosphate group (N/P) experimentally found in the used DNA sample was 3.4 (N, 12.7 wt %; P, 8.32 wt %), while the calculation based on the known (A-T)/(G-C) base pair ratio for salmon sperm DNA gives N/P ) 3.7.25 The expected N/P ratio for the PANisalmon sperm DNA complex structure schematically represented by formula B in Scheme 1 should be 5.7. Elemental analysis for the PANi-DNA complex gives N/P ) 5.5 (N, 9.29 wt %; P, 3.76 wt %) that satisfactorily corresponds to structure B. However, it has been found that the PANi-DNA sample as well as PANi-PSS contains a certain amount of sulfur (S, 2.29 wt %), indicating that residual DBSA molecules are also incorporated in the PANi-DNA complex structure (ca. 6 DBSA per 10 repeating units as in the case of PANi-PSS). Chart 1A,B represents the likely structures of the obtained complexes. (24) Liquier, J.; Pinot-Lafaix, M.; Taillandier, E.; Brahms, J. Biochemistry 1975, 14, 4191-4197. (25) Shabarova, Z. A.; Bogdanov, A. A. Advanced Organic Chemistry of Nucleic Acids; VCH: New York, 1994.

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Table 1. Conductivity Data for PANi-PSS and PANi-DNA Complexes sample

I, mA

U, mV

σ, S/cm

σ (average), S/cm

PANi-DNA, t ) 1 × 10-2 cm

0.1

0.27 0.27 0.52 0.52 0.51 2.54 2.52 2.51 2.49 4.93 4.91 4.68 4.64 4.62 4.61 4.6 9.12 9.06 22.47 22.4 22.37 51.56 47.82 47.21

8.17 8.17 8.49 8.49 8.65 8.69 8.76 8.79 8.86 8.95 8.99 0.94 0.95 0.96 0.96 0.96 0.97 0.97 0.98 0.98 0.99 0.86 0.92 0.93

8.17

0.2 1

2 PANi-PSS, t ) 5 × 10-3 cm

0.1

0.2 0.5 1

8.54 8.77

8.97 0.95

0.97 0.98 0.91

The conductivity of PANi-DBSA films cast on a glass plate from chloroform was measured by the collinear fourprobe technique. The average value obtained for three samples prepared in different experiments in similar conditions was 20 ( 10 S/cm. The above value calculated from 24 measurements varying the sample width corresponds well to the earlier published data.26 The conductivity data for PANi-DNA and PANi-PSS are presented in Table 1. It is seen that the conductivity of PANi-DNA samples is of the same order of magnitude as that of PANiDBSA. However, the conductivity of the PANi-PSS complex was 1 order of magnitude lower. The reason may be caused by a difference in the packing of PANi emeraldine salt in the complex structure. A symmetric singlet line characterizes the ESR spectra of all samples. ESR data for films cast from PANi-DBSA (26) Zheng, W.-Y.; Wang, R.-H.; Levon, K.; Rong, Z. Y.; Taka, T.; Pan, W. Macromol. Chem. Phys. 1995, 196, 2454.

Table 2. Parameters of ESR Spectra of Original PANi and Synthesized Interpolymer Complexes sample

number of R•/g

∆h, Oe

PANi PANi-DBSA PANi-DNA PANi-PSS

6.8 × 1018 5.2 × 1018 52 × 1018 10 × 1018

11.2 1.8 1.8 3.3

solution in chloroform, initial PANi, and PANi-PSS and PANi-DNA powders are represented in Table 2. All complexes have similar spectra widths (∼2-3 Oe) that are appreciably lower than that of the original PANi (about 11 Oe). This indicates a considerable delocalization of unpaired electrons within the complex species. Interestingly, the number of unpaired electrons responsible for the observed ESR spectra does not change essentially upon protonation of PANi by DBSA and subsequent replacement of DBSA by PSS. However, replacement of DBSA by DNA causes the increase of the number of unpaired electrons by 1 order of magnitude. Appearance of ESR active unpaired electrons may be caused by ring twisting in PANi, which disrupts interaction between the radical-cations in PANi chains.27 Thus one may propose somewhat different packing of PANi chains within PANi-PSS and PANiDNA complexes. Conclusion The above data unambiguously show that PANi emeraldine salt can be coupled with either PSS or DNA to form interpolymer complexes via the interchange reaction proceeding between the PANi emeraldine salt and PSS or DNA complexed with the oppositely charged cationic surfactant in the organic solvent. The synthesized interpolymer complexes, especially PANi-DNA, reveal a considerable conductivity. Acknowledgment. This work was supported in part by the Russian Foundation of Fundamental Research (Grant No. 01-03-32779). LA034158J (27) MacDiarmid, A. G.; Zhou, Y.; Feng, Y. Synth. Met. 1999, 100, 131-140.