Highly transparent silanized cellulose aerogels for boosting energy efficiency of glazing in buildings

Abstract

To maintain comfortable indoor conditions, buildings consume ~40% of the energy generated globally. In terms of passively isolating building interiors from cold or hot outdoors, windows and skylights are the least-efficient parts of the building envelope because achieving simultaneously high transparency and thermal insulation of glazing remains a challenge. Here we describe highly transparent aerogels fabricated from cellulose, an Earth-abundant biopolymer, by utilizing approaches such as colloidal self assembly and procedures compatible with roll-to-roll processing. The aerogels have visible-range light transmission of 97–99% (better than glass), haze of ~1% and thermal conductivity lower than that of still air. These lightweight materials can be used as panes inside multi-pane insulating glass units and to retrofit existing windows. We demonstrate how aerogels boost energy efficiency and may enable advanced technical solutions for insulating glass units, skylights, daylighting and facade glazing, potentially increasing the role of glazing in building envelopes.

Flexible and Transparent Bagasse Aerogels for Thermal Regulation Glazing

“…According to the full load production cost model of Liu et al, after replacing the cost of bacteria and wood celluloses with the lower cost of the sugarcane cellulose, a 3 mm-thick mixed aerogel film can be manufactured at an average cost of less than 3 $/ft 2 (see the Supporting Information for details) . Additionally, the mixed aerogel may be further scaled up to a larger size suitable for the practical glazing applications using roll-to-roll processing and ambient pressure drying. , The mixed aerogel has wide potential applications in modern highly glazed buildings for climate regulation owing to its excellent thermal insulation performance and low preparation cost. Furthermore, because the mixed aerogel also exhibits an ultralow density, good mechanical properties, and optical anisotropic properties, it may be used in optical functional devices and mass-sensitive devices.…”

“…19−23 For example, Smalyukh et al prepared a highly transparent wood cellulose aerogel via colloidal self-assembly and procedures compatible with roll-to-roll processing. 24 Waste transformation as the source of valuable materials is a more effective strategy than using commercial crops (e.g., wood, cotton, and bamboo) as raw materials for high-value valorization given socioeconomic and environmental protection. 25,26 As an agro-industrial byproduct resulting from sugar and alcohol industries, bagasse is one of the largest cellulose resources and appropriate for extracting cellulose at low cost (cellulose accounts for approximately 40−50 wt % of bagasse).…”

“…5 Additionally, the mixed aerogel may be further scaled up to a larger size suitable for the practical glazing applications using roll-to-roll processing and ambient pressure drying. 24,62 The mixed aerogel has wide potential applications in modern highly glazed buildings for climate regulation owing to its excellent thermal insulation performance and low preparation cost. Furthermore, because the mixed aerogel also exhibits an ultralow density, good mechanical properties, and optical anisotropic properties, it may be used in optical functional devices and mass-sensitive devices.…”

“…Cellulose, a polymer material with high aspect ratios, high toughness, low density, and low toxicity, is suitable for constructing flexible composite aerogel films. − Currently, researchers have prepared aerogel films from various cellulose sources including bacteria, plants, algae, and tunicates. − For example, Smalyukh et al prepared a highly transparent wood cellulose aerogel via colloidal self-assembly and procedures compatible with roll-to-roll processing . Waste transformation as the source of valuable materials is a more effective strategy than using commercial crops (e.g., wood, cotton, and bamboo) as raw materials for high-value valorization given socioeconomic and environmental protection. , As an agro-industrial byproduct resulting from sugar and alcohol industries, bagasse is one of the largest cellulose resources and appropriate for extracting cellulose at low cost (cellulose accounts for approximately 40–50 wt % of bagasse). − However, the inefficient treatments of bagasse, especially treated as industrial waste in the industry, not only waste this good cellulosic resource but also pollute the environment .…”

Highly Transparent, Temperature-Resistant, and Flexible Polyimide Aerogels for Solar Energy Collection

“…However, most organosiloxane aerogels are opaque or translucent due to the presence of numerous functional groups and grafts that scatter light intensely . To investigate aerogel with high transmittance, some scholars have turned their attention to cellulose-based aerogel. , Smalyukh et al have successfully created a highly transparent aerogel using biopolymer cellulose, which also developed a new type of aerogel-based window using colloid self-assembly and a program that was compatible with roll-to-roll processing. The aerogel boasts an impressive 97–99% visible light transmittance, surpassing that of glass, with only 1% haze and lower thermal conductivity than still air.…”