Self‐assembled monolayers (SAMs) are excellent models for studying interfacial reactions. Here monolayer chemistry is reviewed, focusing on the features that have no analogues in solution chemistry. The growth of surface‐attached polymers, intrafilm reactions, chemistry, photochemistry and reactivity issues are all discussed.

Pressure-area isotherms and surface potential data are presented for octadecyl methyl sulphoxide (OMS) and ( + )-octadecyl p-tolyl sulphoxide (OTS). The surface potential measurements indicate very clearly that both compounds are anchored at the water surface by the SO group and that the plateau in the pressure-area isotherm of OTS is the result of significant molecular orientation. The Demchak and Fort model for relating group dipole moments to the surface potential of floating Langmuir monolayers is reviewed and found to be applicable to a number of compounds. However, the values deduced by these authors for the local permittivities are not appropriate for compounds with long aliphatic chains. By drawing on previously published work a new set of values has been deduced which seems to be more applicable to such compounds and to the sulphoxides investigated here.

Parting is such sweet sorrow"-Romeo and Juliet.In reactions in which bonds are broken, part of one reactant, the leaving group, becomes detached. This Account is concerned with leaving groups which depart with the bonding electron pair. Such groups are termed "nucleofuges".Nucleofuges (Z) figure in two prominent types of reaction:

The kinetics of alkaline hydrolysis of ester groups in self-assembled monolayers (SAMs) were monitored by a combination of atomic force microscopy (AFM) on the nanometer scale and FT-IR spectroscopy in the continuum limit. The main objective was to study surface reactions in situ with chemical specificity, from the nanometer perspective, using an atomic force microscope. This could not be achieved by conventional AFM friction or force measurements due to insufficient resolution, and instrumental or thermal drift, respectively. These problems were circumvented by a novel approach, which we termed "inverted" chemical force microscopy (ICFM). In ICFM, chemical reactions, which take place at the surface of the tip coated with reactants, are probed in situ by force-distance measurements on a scale of less than 100 molecules. The pull-off forces of different reactive SAMs were shown to vary with the extent of the reaction. Reactivity differences for these monolayers observed in this manner by AFM on the nanometer scale agree well with macroscopic behavior observed by FT-IR and can be related to differences in the SAM structure. These results, together with additional force microscopy data, support the conclusion that, for closely packed ester groups, the reaction spreads from defect sites, causing separation of the homogeneous surfaces into domains of reacted and unreacted molecules.