Smart and robust phase change cellulose fibers from coaxial wet-spinning of cellulose nanofibril-reinforced paraffin capsules with excellent thermal management.

Phase change fibers (PCFs), incorporating with diverse phase change materials (PCMs) such as paraffin wax (PW), have been recognized as one of the effective strategies for fabricate smart thermoregulatory textiles. However, some fatal defects exist in traditional paraffin-cellulose-based PCFs, including the paraffin leakage and the low fiber strength. In this work, we herein propose a facile method to prepare uniform and stable paraffin emulsions stabilized by cellulose nanofibrils (CNFs), followed by a simple coaxial wet spinning to develop smart and robust cellulose-based PCFs for human body temperature management. Benefiting from the CNF-reinforced encapsulation, the stability of paraffin capsules and the compatibility of cellulose and paraffin are indeed promoted, thus allowing the cellulose-based PCF with excellent mechanical strength, leakage prevention, and thermal regulation. As a result, the as-prepared PCF, namely CNF1-PE/PW with optimal 1 wt% CNF1 loading, features a high tensile stress of 10.95 MPa at a strain of 111.2 % and a phase-change enthalpy value of 140.24 J/g with a slight paraffin leakage rate of 0.9 %. Moreover, the corresponding wearable fabric exhibits an excellent thermal storage and release recyclability even after 50 cycles. Therefore, this study provides a new idea for the development of intelligent cellulose-based phase change fiber materials.

A one-stone-two-birds strategy for cellulose dissolution, regeneration, and functionalization as a photocatalytic composite membrane for wastewater purification.

Photocatalytic membranes integrate membrane separation and photocatalysis to deliver an efficient solution for water purification, while the top priority is to exploit simple, efficient, renewable, and low-cost photocatalytic membrane materials. We herein propose a facile one-stone-two-birds strategy to construct a multifunctional regenerated cellulose composite membrane decorated by Prussian blue analogue (ZnPBA) microspheres for wastewater purification. The hypotheses are that: 1) ZnCl2 not only serves as a cellulose solvent for tuning cellulose dissolution and regeneration, but also functions as a precursor for in-situ growth of spherical-like ZnPBA; 2) More homogeneous reactions including coordination and hydrogen bonding among Zn2+, [Fe(CN)6]3- and cellulose chains contribute to a rapid and uniform anchoring of ZnPBA microspheres on the regenerated cellulose fibrils (RCFs). Consequently, the resultant ZnPBA/RCM features a high loading of ZnPBA (65.3 wt%) and exhibits excellent treatment efficiency and reusability in terms of photocatalytic degradation of tetracycline (TC) (90.3 % removal efficiency and 54.3 % of mineralization), oil-water separation efficiency (>97.8 % for varying oils) and antibacterial performance (99.4 % for E. coli and 99.2 % for S. aureus). This work paves a simple and useful way for exploiting cellulose-based functional materials for efficient wastewater purification.

Bioinspired construction of petal-like regenerated PVDF/cellulose fibers for efficient fog harvesting.

Water collection from atmospheric fog was deemed to be an efficient and sustainable strategy to defuse the freshwater scarcity crisis. Fog harvesting and trapping fibers, therefore, has aroused extensive interest due to their ease of preparation, weave, and use. However, the traditional fibers used in fog collector usually have a low fog collection capacity and efficiency because of their unreasonable morphology and structure design. Herein, we proposed a simple process to construct advanced fibers using a one-step wet spinning of hydrophobic polyvinylidene fluoride (PVDF) and hydrophilic cellulose mixture fiber for fog harvesting. The as-prepared fibers featured a petaloid structure and surface hydrophobic gradient, thus facilitating fog deposition, water droplet formation, and drainage. The unique longitudinal groove structure above enabled the hybrid fiber to achieve an excellent fog collection efficiency of 2750.26 mg/cm2/h per monofilament, which outstripped most of other fiber materials. When woven these fibers were in a longitudinal array network with an interval of 1 mm, and the fog collection efficiency can maintain at 10.30 L/m2/h. Therefore, this work provided a new strategy for further exploration of effective fog collection by cellulose-based fiber materials.