Highly Transparent All‐Polysaccharide Composite Films with Tailored Transmission Haze for Light Manipulation

Abstract

Low‐cost light management films that completely originate from natural polymers for biodegradable optoelectronics are a growing trend with great demand in the near future, for example, highly transparent and hazy films. Herein, a novel green method simply based on the solubility difference between cellulose and chitosan in ionic liquid is proposed to cast all‐polysaccharide transparent films with customized transmission haze. The dissolved cellulose in 1‐Allyl‐3‐methylimidazolium chloride (AmimCl) ionic liquid serves as matrix. The insoluble chitosan is deliberately dispersed in the matrix, which can maintain its original particle size due to its poor solubility in AmimCl and can significantly increase the surface roughness of the composite film and hence functions as the light scatterer. Eventually, an all‐polysaccharide composite film (Cel/CS) with high transmittance (>84.8%) and tunable haze (10–93%) is prepared using different coagulating bath and drying methods. The film is highly suitable for large‐scale continuous production and sufficient to satisfy the varying haze requirements of different applications, including flexible lighting and displays, antireflection and anti‐glare coatings, and privacy protection.

Sustainable and Superhydrophobic Lignocellulose-Based Transparent Films with Efficient Light Management and Self-Cleaning

“…Typically, light-management films are composed of substrate materials and fillers. 9 The nonbiodegradable and nonrenewable petroleum-based plastics are commonly used as substrates, which are prone to cause serious secondary pollution. 10 Natural cellulose nanofibril (CNF) films have recently been applied to the field of light management.…”

Flexible, Transparent, and Hazy Composite Cellulosic Film with Interconnected Silver Nanowire Networks for EMI Shielding and Joule Heating

“…On the one hand, the loose and uniform porous structure (an average pore size of ∼ 30 μm) is beneficial for uniform infiltration of epoxy resin to achieve high optical transparency. On the other hand, the cellulose fibers with an appropriate diameter (5–20 μm, as shown in Figure b), larger than the wavelength of the optical wave (400–800 nm), can be an ideal medium for Mie scattering of light . After infiltrating with epoxy resin, the obtained TCP exhibited a relatively flat and smooth surface without cracks (Figure c1).…”

“…On the other hand, the cellulose fibers with an appropriate diameter (5−20 μm, as shown in Figure 1b), larger than the wavelength of the optical wave (400−800 nm), can be an ideal medium for Mie scattering of light. 25 After infiltrating with epoxy resin, the obtained TCP exhibited a relatively flat and smooth surface without cracks (Figure 1c1). As shown in Figure 1c2, a densely packed structure of TCP can be observed clearly because the uniformly infiltrated epoxy resin removed the nanoscale porosity of the cellulose network, resulting in favorable light transmission and optical transparency of TCP due to the regulated optical interface and reduced light scattering between cellulose fibers and air (inset of Figure 1a).…”

Strong Cellulose-Based Light-Management Film with Ultraviolet Blocking and Near-Infrared Shielding Performance

“…Of note, the enhanced light scattering increased the light propagation distance and led to a more uniform incident light distribution (Figure 3b 3 ,c 3 ), which might soften harsh sunlight and provide comfortable indoor lighting. 36,37 The final film was flexible and tough. It could be folded into certain shapes and then unfolded without apparent flaws (Figure 3d).…”