enrugamento

Enrugamento is the process by which a surface develops wrinkles or creases, due to differential contraction, compression, or moisture loss. The term is used across disciplines to describe both temporary and permanent surface deformations.

Etymology: The word comes from the Portuguese root rug, meaning wrinkle, with the productive prefix en-. In technical contexts, enrugamento is often interchangeable with wrinkle or creasing, though it specifically connotes a deformed surface rather than a produced fold.

Causes and mechanisms: Wrinkling results from competing forces that cause a material to contract or buckle while the surrounding constraint remains fixed. Typical causes include mechanical compression, differential shrinkage during drying or cooling, thermal cycling, and hydration or dehydration in porous materials. Wrinkles can be reversible (elastic recovery) or irreversible (plastic deformation, fracture).

Domains and examples: In textiles, enrugamento refers to fabric creasing caused by washing, wear, or improper drying. In paper and cardboard, humidity changes induce warping and creasing. In plastics and laminates, surface wrinkling can occur from mismatched layers or overmolding. Biology uses the term for leaf curling and skin wrinkles due to aging.

Management: Preventing enrugamento involves controlling humidity and temperature, conditioning materials before processing, pre-shrinking or relaxing treatments, and using surface coatings or composite layers that accommodate strain. When wrinkles are undesirable, choosing compatible substrates and processing parameters reduces risk; when intentional, wrinkle patterns are engineered for texture.