Surface-Chemistry Mapping of Printed Photopolymers

The outer surface of a printed photopolymer is not necessarily a representative slice of its bulk network. Oxygen inhibition, contact with a vat film or build platform, washing, secondary exposure, abrasion, migration and storage can produce a chemically and physically distinct interphase. Surface analysis is therefore useful for diagnosing adhesion failures, wetting drift, residues and unexpected functional response, but no single technique can identify all of these causes.

This review defines a bounded measurement architecture for mapping the surface chemistry of vat-photopolymerised and related printed photopolymers. X-ray photoelectron spectroscopy provides elemental and chemical-state information from the near surface; time-of-flight secondary-ion mass spectrometry provides fragment-sensitive spectra and chemical images; attenuated-total-reflectance Fourier-transform infrared spectroscopy probes vibrational groups over a larger interaction volume; and contact-angle measurements report a coupled wetting response rather than composition alone. The review connects sampling, controls, mapping, ageing and contamination attribution. Its central conclusion is that contamination is an inference supported by converging evidence, not a label generated by one peak or one water droplet. A defensible study preserves specimen history, uses clean and deliberately contaminated controls, separates topography from chemistry, and states the depth and spatial scale represented by every result.