Approved for Public release; reproduction is permitted for any purpose of The United States Government; distribution unlimited 17. DISTRIBUTION STATEMENT (of the obetract entered In Block 20, It different from Report) Distribution of this document is unlimited, Ia. SUPPLEMENTARY NOTES Prepared for Publication in the Journal of Physical Chemistry 19. KEY WORDS (Continue on reveree aide if necessary and Identify by block number) conducting polymers, njicroelectrochemistry, molecular electronics modified electrodes 20. ABSTRACT (Continue on reverse olde It neceeeary and Identify by block number) Attached DO I JAN73 1473 EDITION OF I NOV

We describe a high-resolution, high-sensitivity negative-tone photoresist technique that relies on bottom-up preassembly of differential polymer components within cylindrical polymer brush architectures that are designed to align vertically on a substrate and allow for top-down single-molecule line-width imaging. By applying cylindrical diblock brush terpolymers (DBTs) with a high degree of control over the synthetic chemistry, we achieved large areas of vertical alignment of the polymers within thin films without the need for supramolecular assembly processes, as required for linear block copolymer lithography. The specially designed chemical compositions and tuned concentric and lengthwise dimensions of the DBTs enabled high-sensitivity electron-beam lithography of patterns with widths of only a few DBTs (sub-30 nm line-width resolution). The high sensitivity of the brush polymer resists further facilitated the generation of latent images without postexposure baking, providing a practical approach for controlling acid reaction/diffusion processes in photolithography.

The homoleptic arylisocyanide tungsten complexes, W(CNXy) 6 and W(CNIph) 6 (Xy = 2,6dimethylphenyl, Iph = 2,6-diisopropylphenyl), display intense metal to ligand charge transfer (MLCT) absorptions in the visible region (400−550 nm). MLCT emission (λ max ≈ 580 nm) in tetrahydrofuran (THF) solution at rt is observed for W(CNXy) 6 and W(CNIph) 6 with lifetimes of 17 and 73 ns, respectively. Diffusioncontrolled energy transfer from electronically excited W(CNIph) 6 (*W) to the lowest energy triplet excited state of anthracene (anth) is the dominant quenching pathway in THF solution. Introduction of tetrabutylammonium hexafluorophosphate, [Bu n 4 N][PF 6 ], to the THF solution promotes formation of electron transfer (ET) quenching products, [W(CNIph) 6 ] + and [anth] •− . ET from *W to benzophenone and cobalticenium also is observed in [Bu n 4 N][PF 6 ]/THF solutions. The estimated reduction potential for the [W(CNIph) 6 ] + /*W couple is −2.8 V vs Cp 2 Fe +/0 , establishing W(CNIph) 6 as one of the most powerful photoreductants that has been generated with visible light.

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Microelectrochemical "transistors" can be prepared by connecting two closely spaced (approximately 1.2 µ ) Au microelectrodes (0.1 µ thick X 2.4 µ wide X 50 µ long) with anodically grown poly(3-methylthiophene). The amount of poly(3methylthiophene) used involves about 10-7-10-6 mol of monomer/cm1 2. Poly(3-methylthiophene) can be platinized by electrochemical reduction of PtCl42' at the pair of coated electrodes. The change in conductivity of poly(3-methylthiophene) with change in redox potential is the basis for amplification of electrical or chemical signals; the conductivity varies by 5-6 orders of magnitude upon change in potential from +0.2 (insulating) to +0.7 (conducting) V vs. SCE in aqueous electrolyte. The Pt equilibrates poly(3-methylthiophene) with the 02/H20 or H20/H2 redox couples. [Poly(3-methylthiophene)/Pt]-based transistors are shown to be viable room-temperature sensors for 02 and H2 in aqueous solution. 02 reproducibly turns "on" the device, with 1 atm of O2/0.1 M HC104/H20 showing 0.7-mA /D at a VD = 0.2 V; H2 reproducibly turns "off" the device, with 1 atm of H2/0.1 M HC104/H20 showing less than 20-nA ID at a VD = 0.2 V, where VD (drain potential) is the applied potential between the two Au microelectrodes and /D (drain current) is the current that passes between the two microelectrodes.The turn "on" with 02 is complete within 2 min, and the turn "off" with H2 is complete within 0.3 min. A platinized microelectrode of a dimension similar to the microelectrochemical transistor shows only 1,0-n A reduction current upon exposure to 1 atm of 02; the current amplification of the transistor is thus a factor greater than 105. The transistor device can also reproducibly respond to pH changes in the pH range of 0-12, when there is a constant 02 concentration; there is a reproducible change in ID to alternate flow of a pH 5.5/pH 6.5 stream for over 10 h. The device responds to an injection of 10"6 L of 0.1 M HC104 into an effluent stream of 0.1 M NaC104 (flowing at 2.0 mL/min) within 4 s. Study of the resistance properties of [poly(3-methylthiophene)/Pt] vs. potential reveals that Pt has little effect on the intrinsic conductivity of poly(3methylthiophene). Rather, the role of Pt is purely as a catalyst to allow equilibration of 02 and H2 with the polymer. The amount of Pt used is approximately 10"7 mol/cm2, and microscopy shows Pt to be present as particles of less than 0,1 -µ size.(4) (a)