Technology and the built world

Polycarbazole

Polycarbazole is a conducting polymer formed by linking carbazole units through oxidative coupling, valued for chemical stability and used in OLEDs, solar cells, sensors, and corrosion protection coatings.

Polycarbonate e-passport

A polycarbonate e-passport is a biometric passport with a data page of fused polycarbonate layers, where details are laser-engraved and a contactless chip is embedded, first issued by Finland in 1997.

Polycarbonate recycling

Polycarbonate recycling is the recovery of waste polycarbonate, an engineering plastic used in electronics and optics, through mechanical, solvent, or chemical routes back into monomers and chemicals.

Polycarbosilane

Polycarbosilane is an organosilicon preceramic polymer that converts to silicon carbide when heated, used mainly to make SiC ceramic fibers and ceramic matrix composites for aerospace.

Polycom

Polycom, Inc. was an American communications equipment company founded in 1990, best known for the SoundStation conference phone and videoconferencing systems; Plantronics acquired it in 2018.

Polycrystalline diamond

Polycrystalline diamond (PCD) is a synthetic engineering material of diamond particles sintered into a coherent solid, often with a cobalt binder, used mainly for cutting tools, drill bits, and wear parts.

Polycrystalline silicon

Polycrystalline silicon, also called polysilicon, is high-purity silicon of many small crystals joined by grain boundaries, made by the Siemens process as feedstock for solar wafers and chips.

Polycrystalline SnSe thermoelectric

Polycrystalline tin selenide (SnSe) is a bulk, multi-grain form of the layered semiconductor SnSe, a thermoelectric material that converts heat into electricity and is cheaper and more scalable to make than single crystals.

PolyDADMAC

PolyDADMAC, or poly(diallyldimethylammonium chloride), is a water-soluble cationic polyelectrolyte whose positive charge neutralizes negatively charged particles, so they clump and settle out in water treatment.

Polydeuces (moon)

Polydeuces (Saturn XXXIV) is a small Trojan moon of Saturn, discovered by Cassini in 2004, trailing Dione by 60 degrees near its L5 Lagrange point.

Polydiketoenamine

Chemically recyclable polydiketoenamine (PDK) is a family of plastics that depolymerize in strong acid back to pristine monomers, first reported at Lawrence Berkeley National Laboratory in 2019.

Polydioxanone

Polydioxanone (PDO, also poly-p-dioxanone or PDS) is a synthetic, absorbable semi-crystalline polyester used in surgical sutures and implants, degrading in the body by hydrolysis and first marketed by Ethicon in 1983.

Polydispersity index

The polydispersity index (PDI) is the ratio of a polymer's weight-average to number-average molar mass, measuring how wide its chain lengths are; IUPAC renamed it dispersity, Đ, in 2009.

Polydopamine nanoparticles

Polydopamine nanoparticles (PDA NPs) are nanoscale particles of polydopamine, a mussel-inspired synthetic polymer formed by oxidative polymerization of dopamine. They strongly absorb near-infrared light, enabling photothermal cancer therapy.

Polyelectrolyte

A polyelectrolyte, also called a polymer electrolyte, is a polymer with a substantial portion of its units bearing ionic or ionizable groups, like DNA and proteins.

Polyester fiber

Polyester fiber is a manufactured synthetic textile fiber, overwhelmingly polyethylene terephthalate, first marketed in 1951 and the world's most produced fiber at 59% of global output in 2025.

Polyether ketone ketone

Polyether ketone ketone (PEKK) is a semi-crystalline thermoplastic in the polyaryletherketone family, invented in the 1960s for the Apollo program and used in aerospace and medical implants.

Polyetherimide

Polyetherimide (PEI) is an amorphous thermoplastic, sold as ULTEM since General Electric introduced it in 1982 and now produced by SABIC, combining high heat resistance, strength, and inherent flame retardancy.

Polyethersulfone

Polyethersulfone (PESU, often abbreviated PES) is an amber-transparent engineering thermoplastic with a glass transition near 225 °C, used in dialysis membranes and sterilizable medical equipment.

Polyethylene glycol treatment

Polyethylene glycol (PEG) treatment is a conservation method that impregnates waterlogged archaeological wood with PEG, replacing water inside the cells so the wood does not crack or shrink when dried.

Polyethylene oxide solid electrolyte

A polyethylene oxide solid electrolyte dissolves lithium salts in poly(ethylene oxide) to conduct lithium ions, first reported in 1973 and used in Bolloré's LMP battery.

Polyethylene separator

A polyethylene separator is a microporous PE membrane in lithium-ion batteries that blocks electrode contact while letting lithium ions pass, with a thermal shutdown near 130–140 °C.

Polyethyleneimine

Polyethyleneimine (PEI), also called polyaziridine, is a cationic polymer of ethyleneimine units existing in branched and linear forms, widely used for DNA and RNA transfection and carbon dioxide capture.

Polyfluorene

Polyfluorene is a conjugated polymer of fluorene units whose soluble derivatives, such as PFO, are among the most studied blue-emitting materials for polymer light-emitting diodes, lasers, solar cells, and transistors.

PolyForm licenses

PolyForm licenses are a suite of eight standardized source-available software licenses from the PolyForm Project, first released in 2019 with restrictions such as noncommercial or internal use.

Oct 26, 2026

Polyglot persistence

Polyglot persistence: use of multiple, specialized database technologies within one application or enterprise, each chosen for its data's needs; introduced via Neal Ford's polyglot programming idea, popularized by Martin Fowler, central to NoSQL and microservices.