Langmuir 1988, 4 , 192-195
192
systems, where octylammonium octanoate is replaced by a long-chained a l ~ o h o l . ' ~ J ~ J ~ Further work is going on in our laboratory to obtain a better understanding of the thermodynamics in different A+A- systems. The experimental work is concentrated on obtaining phase diagrams for A+A- systems with different A+ and A- head groups, but the solubility of long-chained alcohols and other molecules in different A+A--water
systems is also investigated. The results may be helpful to clarify the molecular origin of the hydration force, but they may also become useful for technical applications.
Acknowledgment. Prof. Bjorn Lindman and Prof. I%kan Wennerstrom are gratefully acknowledged for many comments and suggestions. Registry No. Na+A-, 1984-06-1;A+A-, 17463-34-2.
Unusual Catalytic Activity of Anionic Surfactant Analogues of 4-(Dimethy1amino)pyridinein Carboxylate Ester Hydrolyses Alan R. Katritzky,*t Bradley L. Duell,t Barry L. Knier, and H. Dupont Dursti Department of Chemistry, University of Florida, Gainesville, Florida 32611, and Applied Chemistry Branch, Chemistry Division, U S . Army Chemical Research and Development Center, Aberdeen Proving Ground, Maryland 21010-5423 Received June 25, 1987 Anionic Surfactants containing the 4-(N,N-dialkylamino)pyridinemoiety and incorporating sulfate (2), phosphate (31, sulfonate (51, and carboxylate (7) end groups were synthesized and tested as catalysts for the hydrolysis of 4-nitrophenyl hexanoate (PNPH). Surfactant 2 was the most active, with kz = 38.0 M-' s-' in the absence of added CTAC and 62.2 M-'s-' in 0.001 M CTAC. The other derivatives tested (3 and 7) were still twice as active as neutral, cationic, and zwitterionic surfactants of the same type. Possible reasons for these rate enhancements are discussed.
Introduction In a previous paper,' we reported studies of a series of surfactants incorporating the 4-(N,N-dialkylamino)pyridine moiety as catalysts of fluorophosphate and carboxylate ester hydrolyses. All the compounds displayed catalysis of the hydrolysis of p-nitrophenyl hexanoate, although none efficiently catalyzed that of fluorophosphate. The most surprising finding was that the single anionic derivative, sodium 10-[butyl(6pyridinyl)amino] decyl sulfate (2))was more active by 1order of magnitude over neutral, cationic, and zwitterionic analogues. Compound 2 catalyzed the hydrolysis at pH 8.6 of Cnitrophenyl hexanoate with Itz = 38.0 M-'s-l, which compared favorably to hydrolyses utilizing the active o-iodosobenzoate catalysts developed by Moss and co-workers.2-4 The superior activity of 2 compared to its analogues of different charge type was unexpected, since ester hydrolyses under basic conditions, although readily enhanced by cationic surfactants (e.g., cetyltrimethylammonium chloride (CTAC)), are normally retarded by anionic surfactants (e.g., sodium dodecyl ~ u l f a t e ) . ~ We have now prepared three additional related anionic 4-(dialky1amino)pyridine surfactants (3, 5, 7; Scheme I) and report in the present paper their synthesis and catalytic activity in the hydrolysis of PNPH, in an effort to clarify this situation. Synthesis The anionic 4-(dialky1amino)pyridinesurfactants were all synthesized from 10-[butyl(4-pyridinyl)amino]-l-decanol (1)' according to the plan outlined in Scheme I. We previously1 reported the synthesis of sulfate 2 from alcohol 1 by reaction with chlorosulfonic acid. Phosphate
t University of Florida.
* U.S.Army Chemical Research and Development Center. 0743-7463/88/2404-0192$01.50/0
ClSOsH (41 %)
1. DCCINCCHpCHzOP03H2
2.NsOH
I
145%)
-
MsClINEts (95%)
3
4
5
1
KCNIKI
(63%)
8
7
derivative 3 was also prepared in 51% yield directly from 1, by DCC-catalyzed cyanoethyl phosphorylation>followed (1)Katritzky, A. R.; Duell, B. L.; Durst, H . D.Langmuir, in press. ( 2 ) Moss, R. A.; Alwis, K. W.; Bizzigotti,G . 0. J.Am. Chem. SOC.1983, 105, 681. ( 3 ) Moss, R.A,; Alwis, K. W.; Shin, J.4. J.Am. Chem. SOC.1984,106, 2651.
0 1988 American Chemical Society
Langmuir, Vol. 4, No. 1, 1988 193
Surfactant Analogues of 4-(Dimethylamino)pyridine
Table I. '*C NMR Chemical Shift Data ( 6 ) for 4-(Dialkylamino)pyridineAnionic Surfactants 1
2
3
4
5
6
7
8
B 1 0
11121314
::b
X--CH*CH~CH~CH~CH~CH~CH~CH~CH~CH~NCH~CH~&H~CHS
compd
X
solvent CDC13 OH CDC13 OS03H CDC13 OP03Hz CDC13/CD30D OSOzMe CDCl,
1
2
3
4-7
8
9
62.2 67.2 66.0 70.0
32.7 28.7' 29.4 28.4"
25.7 25.1 24.6 24.8
29.3" 28.7" 28.4" 28.4"
26.8 26.0 25.8 26.1
28.9 28.7" 28.4" 28.4O
6
S03H CN
CDC13 CDClS
32.8 28.4" 28.4" 28.4" 26.2 28.4" 50.7b 5O.gb 28.4" 19.4 15.7 27.2" 23.8 27.2" 25.2 27.2" 49.7 49.7 27.2" 18.5
7
COOH
CDCl3
33.2 28.0" 23.7 28.0" 25.6 28.0" 50.3 50.3 28.0" 18.9
DMAP 1
2 3 4
5
"Cluster of peaks centered at this chemical shift.
Kinetic Results and Discussion The anionic surfactants were tested for catalytic activity in the hydrolysis of 4-nitrophenyl hexanoate (PNPH). Catalysts 2 and 7 were utilized as free bases, and 3 as its hydrochloride salt. Limited solubility precluded the testing of sulfonate 5. The procedures utilized for the kinetics measurements were as described in a previous paper.' The results are reported in Table 11, in which values for DMAP and for alcohol 1 are included for the purpose of comparison. Swamp, S. J. Am. Chem. SOC.1986,108,
188. (5)Fendler, J. H.; Fendler, E. J. Catalysis in Micellar and Macromolecular Systems; Academic: New York, 1975; pp 98-120. (6)Tener, G.M. J. Am. Chem. SOC.1961,83,159. (7)Levy, G. C.;Lichter, R. L.; Nelson, G. L. Carbon-13 Nuclear Magnetic Resonance Spectroscopy, 2nd ed.; Wiley-Interscience: New
York, 1980; p 118.
12
13
32.7 28.1 28.4" 28.4"
20.0 19.4 19.1 19.4
4' X 153.1 13.7 152.4 13.3 155.5 12.8 155.5 13.3 155.5 44.7 (CH3) 13.3 142.1 107.7 154.2 12.4 141.1 106.8 153.3 118.5 (CN) 12.8 141.5 107.2 153.8 175.1 (COOH) 14
2' 148.6 149.2 138.9 138.2 138.5
3' 105.6 106.1 106.3 106.3 106.2
These assignments are interchangeable.
by removal of the cyanoethylprotecting group with sodium hydroxide. Sulfonate 5 and carboxylate 7 were prepared via mesylate 4, itself synthesized (95%) by reaction of 1with mesyl chloride in the presence of triethylamine. Treatment of 4 with KZSO3/KIin refluxing ethanol gave 5 in 50% yield, as the hydrochloride salt. Carboxylate 7 was synthesized by reaction of 4 with KCN/KI in refluxing ethanol to give 6 (63%) followed by acidic hydrolysis (87% yield). 13CNMR data for intermediates and final compounds are shown in Table I (alcohol 1 and DMAP are included for comparison purposes). Assignments were based upon comparison to known systems. The chemical shifts are consistent with the structure shown in Table I. Chemical shifts for pyridine carbons C-2', C-3', and C-4' of 1 are essentially the same as those for DMAP. However, compounds 2-7 are hydrochloride salts, and this difference is reflected in the 13C chemical shifts of the pyridine nucleus. Carbon C-2' is shielded by approximately 10 ppm, whereas C-4' is deshielded (by 1-3 ppm) and C-3' is relatively unchanged compared to 1. Similar effects have been reported for other pyridinium ions.' Chemical shifts for the alkyl carbons were also as expected. Carbon C-1 resonated a t 6 62.2 in 1, a t slightly higher values in 2-4, and farther upfield (at 6 30) in 5 and 7. In nitrile 6, C-1 occurred at 6 15.7, which, in combination with the CN resonance a t 6 118.5, was useful as a diagnostic tool for confirming the presence or disappearance of 6. Carbons C-1 and C-2 of phosphate 3 were both split into doublets, with 2J = 5.8 and 3J = 7.3 Hz, respectively, due to 13C-31Pcoupling.
(4) Moss,R. A.; Kim, K. Y.;
10 11 37.8 37.8 49.7b 50.0b 50.5b 50.7b 50.2b 50.4b 50.5b 50.7b
Table 11. Second-Order Rate Constants @CAT) for the Hydrolysis of.p -Nitrophenyl Hexanoate (PNPH) at pH 8.5 ([PNPH] = 5.5 X lod M) kCAT, M-' s-' compd no CTAC 1 mM CTAC 5 mM CTAC 1 (ROH) 1.25 35.6 32.0 2 (ROSOSH) 38.0 62.2 35.8 3 (ROPO3Hz) 2.36 10.0 9.05 7 (RCOOH) 2.69 5.12 3.21 DMAP" 3.68 1.96 1.32 blank (no surfactant) b "DMAP = 4-(dimethylamino)pyridine. Hydrolysis in the absence of surfactant gave a pseudo-first-order rate constant of 6.5 X s-l, which represents background hydrolysis (khyd + koT[OH-]). At the [PNPH] given above, this corresponds to an initial rate of 3.6 X lo4 M s-'. In comparison, using kc^^ for 3 at a concentration of 0.001 M, the initial rate was 130 X lo+' M s-'.
Scheme I1 R-N-
I
(CH2)qo-A-
I
+ R-
N -(CH2+0-A-
R - N T
R'COOH
6-h W
9
Surfactant 2 remains the most effective catalyst in this whole series and is some 15 times better than 3 or 7. However, kz values for 3 and 7 (2.36 and 2.69 M-' s-l, respectively) were still about twice those for neutral surfactant 1 and for the analogous cationic and zwitterionic surfactants, synthesized previously.' The anionic head group thus appears to play a significant role in the catalytic activity of these systems. The relatively high efficiency of the anionic compounds a t first glance appears anomalous since, as mentioned
194
Langmuir, Vol. 4, No. 1, 1988
Katritzky et al.
above, for electrostatic reasons, anionic surfactants normally retard basic hydrolyses. However, other factors can be invoked. Thus, anchimeric assistance of hydrolysis of the 1-acylpyridinium intermediate by the anionic head group could account for the observed enhancements. Electrostatic stabilization of the acylpyridinium intermediate may also be taking place (Scheme 11). Formation of acylpyridinium 8 is known to be the rate-determining step in hydrolyses of the type RCOX RCOOH + HX.8 Electrostatic stabilization of the positive charge in 8 by the anionic group could lower the transition-state energy for its formation and thus increase the rate of formation of 8. Another important factor is the pKa values of the various groups involved. At the pH of the reaction medium (pH 8.5),the 4-(dialky1amino)pyridinegroup (pKa = 9.4*) is approximately90% in the protonated form ( ~ F @ J P Y H + ) . ~ The OS03H and COOH groups (pKa -3 and 4.8, respectivelylO)should both be 100% ionized and the OP03H, moiety (pK, values of -2.1 and 7.21°) approximately 96% in the OPO2- f0rm.l’ Thus,the dominant species present in solution are zwitterionic (9, Scheme 11). Hence, 2, 3, and 7 could act as zwitterionic “bolaform” surfactants (Scheme II).12J3 The surface activity of dicationic bolaforms has been interpreted by the formation of “wicketlike” structures a t the air-water interface.13 Such bolaforms can form micelles if the connecting carbon chain length equals or exceeds 12 (Scheme 111, and these bolaforms are capable of increasing the rate of p-nitrophenyl doodecanoate hydrolysis (by 28-fold at pH This reasoning carries with its significant implications for the surfactants synthesized in this study. The chain lengths in compounds 2,3, and 7 connecting the anionic and the cationic (PyH+)groups are roughly 15 atoms (including N, 0, and S and counting the pyridine ring as 2 atoms), and this allows the chains to form bolaform micelles. The formation of wickeblike species is perhaps even more likely with the dicationic bolaforms because of the oppositely charged head groups involved. This would account for the higher catalytic activity of the “anionic” surfactants, since the other surfactants prepared are incapable of forming such micelles. In solution, the “neutral” and “zwitterionic” surfactants would actually have a net positive charge (+l), whereas the “cationics“ would possess an overall double positive charge (+2). A t the present time, the reason for the high activity of surfactant 2 (ROS03H) relative to 3 (ROPO,H,) and 7 (RCOOH) remains unclear. We are currently in the process of investigating further the precise structures of the species present in solution.
-
-
Experimental Section Methods. All melting pointa are uncorrected and were taken in open glass capillary tubes with a Thomas-Hoover melting point apparatus. IR spectra were obtained on a Perkin-Elmer 283B infrared spectrophotometer. 13C NMR spectra were obtained a t 25 MHz on a JEOL FX-100 NMR spectrometer, referenced to CDC13 (6 77.0), and are reported in Table I. High-resolution mass spectra were obtained on an AEI MS30 mass spectrometer. (8) Scriven, E. F. V. Chem. SOC.Reu. 1983, 12, 129. (9) The percentage of protonated pyridine (PyH+) in a solution of Py is given by the following; % PyH+ = {[PyH+]/([PyH*l + [Pyl)} X 100 = (1 IOPH-PK+~ x io0 = (1 108.5-9.4)-1x.100 = 89%. (10) Gordon, A. J.; Ford, R. A. The Chemrst’s Companion; Wiley-Interscience: New York, 1972; pp 58-59. (11) The percentage of A- in a solution of HA is given by the following: % A- = I[A-]/([A-] [HA])/ x 100 = (1 + 10pK*-pH)-l X 100. (12)Fuoss, R. M.; Chu, V. F. H. J. Am. Chem. SOC.1951, 73, 949. (13) Menger, F. M.; Wrenn, S. J. Phys. Chem. 1974, 78, 1387.
+
+
+
Microanalyses were either performed in house, on a Carlo Erba 1106 elemental analyzer, or by Atlantic Microlabs, Atlanta, GA. Materials. Commercially available reagent grade solvents and reagents were used without further purification. Silica gel filtrations utilized either E. M. Merck or MCB silica gel 60 (230-400 (1) and 10-[bumesh). 10-[Butyl(4-pyridinyl)amino]-l-decanol tyl(4-pyridinyl)amino]-l-decylsulfate (2) were prepared as described previously.’ l0-[Butyl(4-pyridinyl)amino]-l-decylPhosphate (3). Barium (2-cyanoethy1)phosphate dihydrate (0.58 g; 1.73 mmol) and Amberlite IR-120 H.C.P. cation-exchange resin (sulfonic acid, 3 g) were stirred in water (5 mL) until the barium salt dissolved. The solution was passed through a column of the same resin (5 g), washing with water (15 mL). The water was removed by adding dry pyridine (10 mL), evaporating, and repeating the process; a yellow oil was obtained. To this was added 1 (0.51 g; 1.67 mmol) in dry pyridine (10mL) followed by dicyclohexylcarbodiimide (1.38 g; 6.70 mmol) and the mixture stirred at room temperature for 17 h. Water (2 mL) was added, stirring continued for 1 h, then 10% HOAc (50 mL) was added, and the mixture was heated on a steam bath for 2 h. The solvent was evaporated and the residue heated on the steam bath with 0.5 N NaOH (70 mL) for 2 h. After the mixture cooled to room temperature, the solid was filtered and the filtrate acidified and evaporated (via ethanol azeotrope). The semisolid was taken up in absolute ethanol (50 mL), filtered, and evaporated. To the resulting oil was added water (20 mL). The mixture was basified (pH 10) with 2.5 N NaOH and then extracted with EtOAc (2 X 10 mL). After acidificationof the aqueous layer, NaCl was added and the solution extracted with 3:2 CH2Cl2/EtOH (3 X 10 mL). The combined extracts were dried over MgSO, and evaporated to give 0.32 g (45%) of the hydrochloride of 3 as an amber oil: IR (thin film) 3500-2000 (br), 3300 (br), 2930 (e), 2850 (s), 2200,2060,1730,1650 (s), 1545 (s), 1465, 1370, 1210 (br, s), 1080-950 (br, s), 910, 730 (s) cm-’. Anal. Calcd for C1J-13sClN204P”20: C, 51.75; H, 8.69. Found: C, 51.43; H, 8.62. lO-[Buty1(4-pyridinyl)amino]-1-decyl Methanesulfonate Hydrochloride (4). A solution of methanesulfonyl chloride (0.48 g; 4.20 mmol) in CHzClz(4 mL) was added dropwise over a period of 10 min to a solution of 1 (1.24 g; 4.06 mmol) in CHzClz(12 mL) at room temperature. After stirring 3 h, the solution was cooled in ice, triethylamine (0.78 g; 7.72 mmol) and additional methanesulfonyl chloride (0.48 g) were added in one portion, and stirring was continued a t room temperature for 24 h. After addition of CHzClz(20 mL), the mixture was washed with water (20 mL) and 1N HCl(20 mL),dried over MgS04, and evaporated to give 1.63 g of 4 (95%) as an amber oil (4was stored in CHzClz in the refrigerator to prevent decomposition): IR (thin film) 3100-2300 (br), 2930 (s), 2860 (s),1640 (s), 1590 (w), 1545 (s), 1460, 1420 (w), 1345 (s), 1210, 1170 (s), 1100 (w), 1040,970,940,930, 810,730 cm-’; high-resolution mass spectrum ( m / e )(for free base) calcd 384.2447, found 384.2469 (standard deviation 0.0053). l0-[Butyl(4-pyridinyl)amino]decanesulfonicAcid Hydrochloride (5). 4 was taken up in CH2C12,washed with 1 N NaOH, filtered through silica gel, and evaporated to give the free base. The free base (0.24 g; 0.63 mmol), KzSO3 (0.36 g; 2.28 mmol), KI (0.32 g; 1.93 mmol), and EtOH (95%; 1.5 mL) were refluxed for 17 h. Water (10 mL) was added and the ethanol evaporated. The solution was acidified to pH 3-4 and extracted with CHzClz (1 X 15 mL). The organic layer was washed with 1 N HCl (10 mL), dried over MgS04, and evaporated to give 0.13 g (50%) of 5 as a yellow glass: IR (thin film) 3400 (br), 3100-2300 (br), 2920 (s), 2860 (s), 1645 (s), 1550 (s), 1465, 1420, 1370, 1230, 1190 (s), 1110, 1030, 825, 720, 520 (br) cm-’. Anal. Calcd for C1J-135C1Nz03S.2Hz0: C, 51.51; H, 8.87. Found C, 51.89; H, 8.87. ll-[Butyl(4-pyridinyl)amino]undecanenitrile Hydrochloride (6). 4 (0.90 g: 2.13 mmol), KCN (0.56 g; 8.62 mmol), KI (1.20 g 7.23 mmol), and EtOH (absolute; 9 mL) were refluxed for 17 h, at which point more EtOH (5 mL) was added and refluxing was continued for 2 h. Water (20 mL) was added and the ethanol evaporated. The mixture was basified with 2.5 N NaOH and extracted with CHzClz(1X 25 mL). The organic layer was evaporated, and the resulting oil was taken up in CHzClz (7 mL), washed with 1 N HC1 (7 mL), and passed through a pad
Langmuir 1988,4, 195-200 of silica gel (5 g), washing with 2 4 % MeOH in CHZClp Evaporation of the eluate gave 0.47 g of 6 (63%)as an amber oil: IR (thin film) 3420 (br), 2920 (s), 2850 (s), 2230 (w), 1640 (s), 1550 (s), 1460, 1420, 1365, 1185, 1100 (w), 915 (w), 820, 725 cm-'. Anal. Calcd for CmH34C1N3.3H20: C, 59.17; H, 9.93. Found: C, 59.29; H, 8.93. ll-[Butyl(4-pyridinyl)amino]undecanoic Acid Hydrochloride (7). 6 (0.42 g; 1.19 mmol) and concentrated HCl(4 mL) were refluxed for 15 h, then more concentrated HCl(2 mL) was added, and refluxing was continued for 2 h more. After cooling to room temperature, the mixture was extracted with 3:l CH2Cl2/MeOH(3 X 4 mL), and the extracts were dried over MgSOl and passed through a pad of silica gel (2 g), washing with 3:l CH2Cl2/MeOH(40 mL). Evaporation of the eluate gave 0.37 g (87%)of 7 as an amber glass: IR (thin film) 3600-2500 (br), 3400 (br),2960 (s),2930 (s), 1720 (s), 1650 (s), 1550 (s), 1465,1425, 1370, 1190 (s), 1100 (w), 1030 (w), 820, 730 cm-'. Anal. Calcd for C&~ClNz0z~2Hz0: C, 59.02; H, 9.66. Found C, 59.61; H, 9.22. The free base (zwitterion)of 7 was utilized for rate measurementa and was prepared by washing a chloroform solution of 7
195
with 1 N NaOH, boiling the solution with charcoal, filtering it through silica gel with 5-15% MeOH/CH2Cl2,and evaporating the filtrate to give a thick, colorless oil, which slowly crystallized to colorless needles. Spectra were identical with those for 7, except that the 13C NMR spectra lacked the resonance at S 175.1 and the IR spectra lacked the broad adsorption at 3600-2500 cm-' and possessed an additional band at 920 cm-*. Anal. Calcd for CzoHMNz02.2Hz0: C, 64.83; H, 10.34. Found C, 64.74, H, 10.16. Kinetics. Rate measurements were carried out utilizing pnitrophenyl hexanoate (PNPH) by methods discussed in an earlier paper.'
Acknowledgment. We thank the Army Research Office for financial support and Drs. Cliff Bunton and Fred Menger for helpful discussions. Registry No. 1, 110027-37-7;2, 111823-07-5;2 (freebase), 110027-38-8;3, 111823-01-9;4, 111823-02-0;5, 111823-03-1;6, 111823-04-2;7, 111823-05-3;7 (freebase), 111823-06-4;PNPH, 956-75-2;DMAP, 1122-58-3;NC(CH2)z0P03Hz.Ba,5015-38-3.
Study of Langmuir-Blodgett Films for KrF Excimer Laser Resist K. Ogawa,* H. Tamura, M. Hatada,? and T. Ishihara Semiconductor Research Center, Matsushita Electric Ind. Co., Ltd., 3-15,Yagumo-Nakamachi, Moriguchi, Osaka, 570 Japan, and Osaka Laboratory for Radiation Chemistry, Japan Atomic Energy Research Institute, 25-1,Mii-Minami Machi, Neyagawa, Osaka, 572 Japan Received March 18,1987. I n Final Form: July 28,1987 Studies in an attempt to prepare photosensitive Langmuir-Blodgett (LB) films and photochemical reactions of LB films induced by a KrF excimer laser (EX) beam have been carried out on three fatty acids of diacetylene derivatives (tricosadiynoicacid, pentacosadiynoic acid, and heptacosadiynoic acid), w-tricocynoic acid, and octadecylacrylic acid. The patterning of the LB films was carried out by using the EX stepper. Among five compounds, pentacosadiynoic acid gave the best result with 0.3-pm resolution on mol/L the LB films which were prepared from Langmuir (L) films on an aqueous subphase containing Ca2+at 25 mN/m. Spectroscopic studies on the structure of the LB film indicate that the patterning is caused by cross-linking at 1,4 positions of diynoic groups. The resolution (0.3 pm) obtained in the present study is determined by the resolution limit of the optical system of the EX stepper developed for this purpose, which is the hkheat This technique will be useful for fabrication of 64-Mbit - resolution theoretically- expected. D-RAMS.
Introduction Recent progress in semiconductor technology has required photolithography to perform in the 0.5-pm region; however, the currently available photolithography relying on UV or visible light has a limitation. In order to improve the performance, several methods have been proposed, including high NA and short wavelength type reductionprojective light exposure apparatus (stepper), direct draw electron beam (EB) exposure apparatus, X-ray exposure apparatus (X-ray stepper),' and excimer laser exposure apparatus (EX ~ t e p p e r ) . ~ - ~ On the other hand, the available diameter of the wafer currently is increasing to 8 in. A technique of uniform, thin coating of the resist on these wafers is needed to obtain patterns below 0.5 pm in the case of EX exposure method. The available spin coating method is no longer workable for this purpose. For this purpose, we can use the preparation method of Langmuir-Blodgett,B,' which Osaka Laboratory for Radiation Chemistry. 0743-7463/88/2404-0195$01.50/0
is being developed for making molecular devices.a There already are some papers studying the EB exposure on LB films, i.e., by A. Barraudg and others.lOJ1 In Barraud's paper, patterns of 600-Aline and space were fabricated by using a-tricosenoic acid. But the EB expo(1)Spears, D. L.; Smith, H. I. Solid State Technol. 1972,15, No. 7, 21. (2)Jain, K.; Willeon, C. G.; Lin, B. J. ZBM J. Deu. 1982,26, 151. (3) Kawamura, Y.;Tyoda, K.; Nanba, S. J. Appl. Phys. 1982,53(9), 6489. (4)Pol, V.;Bennewitz, J. H.; Escher, G. C.; Feldman, M.; Firtion, V. A.; Jewell, T. E.; Wilcomb, B. E.; Clemens, J. T. Proc. SPIE-lnt. SOC. Opt. Eng. 1986, March 6,663-01. (5)Orvek, K. J.; Palmer, S. R.; Garza, C. M.; Fuller, G. E. Proc. SPZE-Znt. SOC.Opt. Eng. 1986, March 6,631-12. (6)Blodgett, K.J. Am. Chem. SOC. 1935,57,1007. (7)Gaines, G. L., Jr. Insoluble Monolayers at Liquid-Gas Interface; Interscience:, New York, 1966. (8) Mcalear, J. H.; Wehrung, J. M. Dig. Tech. Pap-Symp. VLSZ Tech. 1981,82. (9)Barraud, A. Thin Solid Films 1983,99, 317. (10)Broers, A. N.; Pomerantz, M. Thin Solid Films 1983,99, 323. (11)Fariss, G.; Lando, J.; Rickert, S. Thin Solid Films 1983,99,305.
0 1988 American Chemical Society
