reanneal

Reanneal is the act of annealing again or the process by which a system returns to an annealed state after prior treatment. The term is used in materials science and molecular biology, among other fields, to describe different but related processes aimed at relieving defects and stabilizing structures.

In materials science, reannealing refers to reheating a previously deformed, tempered, or otherwise processed material to a temperature sufficient to enable diffusion and structural rearrangement, followed by controlled cooling. The purpose is typically to relieve residual stresses, restore ductility after work hardening, or refine and modify the microstructure. Conditions such as temperature, time, and cooling rate are chosen to achieve the desired effects; repeated or varied cycles can lead to grain growth, precipitation, or changes in hardness and toughness.

In molecular biology, reannealing (renaturation) describes the reassociation of complementary nucleic acid strands after denaturation, returning single strands to double-stranded form. This process depends on sequence complementarity, strand length, GC content, ionic strength, and temperature. Reannealing under precise conditions is used in hybridization assays, sequencing library preparation, and studies of genome organization, as well as in the PCR workflow where a brief annealing phase allows primers to bind.