Thermotropic and Thermochromic Polymer Based Materials for Adaptive Solar Control

Abstract

The aim of this review is to present the actual status of development in adaptive solar control by use of thermotropic and organic thermochromic materials. Such materials are suitable for application in smart windows. In detail polymer blends, hydrogels, resins, and thermoplastic films with a reversible temperature-dependent switching behavior are described. A comparative evaluation of the concepts for these energy efficient materials is given as well. Furthermore, the change of strategy from ordinary shadow systems to intrinsic solar energy reflection materials based on phase transition components and a first remark about their realization is reported. Own current results concerning extruded films and high thermally stable casting resins with thermotropic properties make a significant contribution to this field.

Flexible Reflective Color Displays using Thermochromic Pigments

“…Thermochromism of organic dyes and inorganic materials (e.g. fluorans, spiropyrans, and luceo dyes) has generally occurred due to rearrangement of molecular structure (e.g., ring opening/closure and tautomeric rearrangement), and an intercalation/de-intercalation effect, respectively [13]. The three thermochromic pigments considered in this paper generate color transitions at 38℃, which is acceptable in terms of achieving low power consumption.…”

An empirical study of a full-scale polymer thermochromic window and its implications on material science development objectives

“…The chemistry of the ligand exchange thermochromic film that was tested is described in [5] as "the rearrangement of ligands around metal ions which cause the formation of metal complexes that increase visible light absorbance with increased temperature." In the patent literature [9], developers describe the thermochromic in detail, where example 294 is similar in composition to what was tested (i.e., slight deviations occurred in amount of materials and type of substrate film used to improve durability and performance).…”

“…Both types have been extensively reviewed in the literature [3][4][5], providing information on the current status of material science developments, switching characteristics of the various material formulations, and an assessment of market maturity. Near-term polymerthermochromicsexhibit absorption but remain transparent in the tinted phase, where absorption is primarily in the visible (VIS) range (wavelengths between 380-780 nm).…”

Smart windows—Dynamic control of building energy performance

“…alter solar and visible light transmittance and reflectance based on window temperature, 11 they have the potential to reduce solar heat gains and subsequently reduce cooling loads 12 when the external conditions exceed those required for occupant comfort. Conversely when 13 the external conditions fall short of those required for occupant comfort, they maintain a 14 degree of optical transparency thus promote the potential for passive solar gain.…”