Nanocellulose: With film forming and transparency, it leads a new direction for green functional films

What is nanocellulose?

Nanocellulose is a nano- scale fiber material prepared by physical, chemical or enzymatic methods using natural cellulose as raw materials. The fiber diameter is generally 5~ 50nanometers and the length can reach several microns. Compared with traditional cellulose, nanocellulose not only retains green characteristics such as renewable and degradable, but also shows excellent mechanical, optical and processing properties because of its nanostructure, making it a globally recognized new generation of high-performance bio-based material.

Where does excellent film-forming and transparency come from?

1. The dense network brought by the nanoscale nanometer scale
has an extremely high specific surface area. The fibers are tightly wound by hydrogen bonds, and can be self-assembled into a continuous and dense three-dimensional network in the aqueous phase, making it easy to prepare a uniform membrane layer with flat surfaces and no holes.

2. The light scattering is extremely small, the light transmittance is high,
and the fiber diameter is much smaller than the visible light wavelength, which can effectively reduce light scattering and impart excellent transparency to the nanocellulose film. The films made of some bacterial cellulose or nanocrystalline cellulose can have a light transmittance of more than 85% .

3. High purity, colorless and odorless
nanocellulose usually does not contain impurities such as lignin, hemicellulose, etc., ensuring that the membrane layer itself is colorless and transparent, and meets food contact and medical requirements.

Multi-scenario value brought by film formation and transparency

Green packaging film
nanocellulose can replace some traditional plastic films and are used in food and pharmaceutical packaging. It not only has high strength and good barrier properties, but also can be completely degraded to meet the requirements of sustainable development.

The transparent and flexible nanocellulose film of
flexible electronics and optical devices can be used as a flexible display screen, solar cell backplane, optical substrate, etc. to improve the light transmittance and structural strength of the device.

Medical biofilm
In medical dressings, transparent membranes facilitate doctors to observe the wound healing process, and at the same time have good biocompatibility and breathability.

Functional coating and surface protection
nanocellulose solution can form a highly translucent protective layer on the surface of wood, paper or plastic, improving wear resistance and water resistance without affecting the appearance of the substrate.

Future development and challenges

With the growth of the ' dual carbon ' target and the demand for bio-based materials, nanocellulose will occupy a more important position in the functional film market with its renewable, degradable, low-carbon and environmental protection properties.

However, to achieve large-scale production and low-cost applications, it is necessary to continuously optimize the cellulose extraction and post-treatment processes, improve production efficiency, and expand modification technologies and composite processes in more scenarios.