No abstract

Direct imaging of ultrathin organic films on solid surfaces is important for a variety of reasons; in particular, the use of such films as ultrathin resists for nanometer scale fabrication and information recording requires that we understand their microstrucure. We have used the Langmuir–Blodgett technique to prepare monolayer and submonolayer films of poly(octadecylacrylate) (PODA) and poly(methylmethacrylate) (PMMA) on graphite substrates. Atomic scale images obtained with the scanning tunneling microscope (STM) and the atomic force microscope of the PODA films showed a variety of structures, including isolated narrow fibrils, parallel groups of fibrils, and an ordered structure consistent with the side chain crystallization expected with that material. The fibrils observed are interpreted as individual polymer chains or small bundles of parallel chains. Images of the PMMA samples show no ordered regions. By applying voltage pulses on the STM tip, we were able to locally modify and apparently cut through the PODA fibrils

SYNOPSISPhysisorption and chemisorption of perfluoropolyethers on solid surfaces is investigated using infrared spectroscopy, microcalorimetry, ellipsometry, X-ray photoelectron spectroscopy, and atomic force microscopy. Physisorbed polymers show shifts of vibrational modes to lower frequencies in a few nanometers thick films, indicating interactions with the solid surfaces. Hydroxyl-terminated polymers are thermally attached to solid surfaces, and their thicknesses increase to saturated values with increasing heating time. The thermally attached thin polymer film consists of strongly physisorbed material as well as chemisorbed material. Strongly physisorbed polymer is slowly displaced from the surface by polar, low-molecular-weight compounds such as water or alcohols. This is to he expected on the basis of microcalorimetric results, which yield higher heats of immersion with water than with reactive perfluoropolyethers. Atomic force microscopy experiments show that the mobility of the polymer remaining on the surface decreases substantially as the amount of the physisorbed material decreases.

Uncla-ssified 22a NAME OF RESPrNS83LE NDIVICUAL I22b. "rELEPHQONE (Incuce Are a Cocei 22c. OFF: YMO Dr. Kennieth J. 4vnnp (202) 696-s. 10 0 O FO0RIM 14 473, 3. MAR 13 APR ea~norl may oe used untio .enaus-ed. SEC'JRIT'y CLASSIICA710 OF-HSPG All other edlitions are oosolete.

Unclassified 22a. NAME OF RESPONSIBLE INDIVIDUAL 22b. TELEPHONE (include Area Code) 22c. OFFICE SYMBOL Dr. Kenneth J. Wynne (202) 696-4410 DO FORM 1473,84MAR 83 APR edtion may be used until exhausted. SFUIr" CLASSIFICATION OF THr!