{'fraction_non_alphanumeric': 0.026, 'fraction_numerical': 0.001, 'mean_word_length': 4.8882352941176475, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Delivering octadecylphosphonic acid self-assembled monolayers on a Si wafer and other oxide surfaces.

We describe a simple experimental approach for delivering self-assembled monolayers (SAMs) of octadecylphosphonic acid (OPA) on many oxide surfaces using a nonpolar medium with a dielectric constant around 4 (e.g., trichloroethylene). This approach readily results in the formation of full-coverage OPA SAMs on a wide variety of oxide surfaces including cleaved mica, Si wafer, quartz, and aluminum. Especially, the availability of delivering full-coverage OPA SAM on a Si wafer is unique, as no OPA SAMs at all could be formed on a Si wafer when using a polar OPA solution. The reason a nonpolar solvent is superior lies in the very fact that the hydrophilic OPA headgroup tends to escape from the nonpolar solution and is thus enriched at the medium-air interface. It is these OPA headgroups seeking a hydrophilic surface that make possible the well-controlled OPA monolayer on an oxide surface.