Substance composed of macromolecules.

Note: Applicable to substance macromolecular in nature like cross-linked
systems that can be considered as one macromolecule.

A polymer (/ˈpɒlᵻmər/; Greek poly-, "many" + -mer, "parts") is a large molecule, or macromolecule, composed of many repeated subunits. Because of their broad range of properties, both synthetic and natural polymers play an essential and ubiquitous role in everyday life. Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteins that are fundamental to biological structure and function. Polymers, both natural and synthetic, are created via polymerization of many small molecules, known as monomers. Their consequently large molecular mass relative to small molecule compounds produces unique physical properties, including toughness, viscoelasticity, and a tendency to form glasses and semicrystalline structures rather than crystals.

The term "polymer" derives from the ancient Greek word πολύς (polus, meaning "many, much") and μέρος (meros, meaning "parts"), and refers to a molecule whose structure is composed of multiple repeating units, from which originates a characteristic of high relative molecular mass and attendant properties. The units composing polymers derive, actually or conceptually, from molecules of low relative molecular mass. The term was coined in 1833 by Jöns Jacob Berzelius, though with a definition distinct from the modern IUPAC definition. The modern concept of polymers as covalently bonded macromolecular structures was proposed in 1920 by Hermann Staudinger, who spent the next decade finding experimental evidence for this hypothesis.

Polymer is a software library used to define and style Web Components. The library is developed by Google. Modern design principles are implemented as a separate project using Google's Material Design design language.

Development

Public development of Polymer began in Nov 14, 2013 with the release of a Promises Polyfill. This steadily expanded into a web design library covering visual styling guidelines (via Material Design), data binding, and a large number of "Core" and "Paper" web components. Core components were originally envisioned to encompass generic functionality that would be essential to most websites, while Paper components were intended to provide more specialized components with Material Design concepts forming a key part of their design. A major milestone was reached with the release of Version 0.5, which was considered the first version of the project ready for use by early adopters.

Google continued to revise the design of Polymer after the release of 0.5, with special consideration given to the performance issues a number of developers found issue with. This culminated with the release of Polymer 1.0 in 2015, which was the first "production ready" version of the library. Version 1.0 significantly improved the performance of Polymer, reducing load times by up to 7 times. With version 1.0 Google split the elements from the Polymer project to clearly distinguish the elements catalog from the Polymer polyfill & webcomponents-sugaring library.