Edward Sacher (1934-2023): Understanding Chemistry at the Interface.

Edward Sacher (1934-2023) devoted more than five decades to understanding the chemistry of surfaces and interfaces. Trained as a physical chemist, he applied fundamental chemical principles to increasingly diverse materials, from polymers and metal-polymer interfaces to nanoparticles, carbon materials, and biological systems. A central theme of his work was the use of surface analytical methods, particularly X-ray photoelectron spectroscopy (XPS), not simply to characterize materials but to reveal the chemical interactions governing their properties and performance. His research connected fundamental interfacial physical chemistry with applications in materials science, microelectronics, nanotechnology, and biomedicine. This commentary traces the development of that scientific program, highlighting selected contributions as well as the laboratory, collaborations, and scientific community he built at École Polytechnique de Montréal.