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Constructing room-temperature phosphorescent materials with multiple emission and special excitation modes is fascinating and challenging for practical applications. Herein, we demonstrate a facile and general strategy to obtain ecofriendly ultralong phosphorescent materials with multi-mode emission, adjustable excitation-dependence, and visible-light excitation using a single organic component, cellulose trimellitate. Based on the regulation of the aggregation state of anionic cellulose trimellitates, such as CBtCOONa, three types of phosphorescent materials with different emission modes are fabricated, including blue, green and color-tunable phosphorescent materials with a strong excitation-dependence. The separated molecularly-dispersed CBtCOONa exhibits blue phosphorescence while the aggregated CBtCOONa emits green phosphorescence; and the CBtCOONa with a coexistence state of single molecular chains and aggregates exhibits color-tunable phosphorescence depending on the excitation wavelength. Moreover, aggregated cellulose trimellitates demonstrate unique visible-light excitation phosphorescence, which emits green or yellow phosphorescence after turning off the visible light. The aggregation-regulated phenomenon provides a simple principle for designing the proof-of-concept and on-demand phosphorescent materials by using a single organic component. Owing to their excellent processability and environmental friendliness, the aforementioned cellulose-based phosphorescent materials are demonstrated as advanced phosphorescence inks to prepare various disposable complex anticounterfeiting patterns and information codes., (© 2023. The Author(s).)

Herein, we present a phosphorescent cationized cellulose derivative by simply introducing ionic structures, including cyanomethylimidazolium cations and chloride anions, into cellulose chains. The imidazolium cations with the cyano group and nitrogen element promote intersystem crossing. The cyano-containing cations, chloride anions and hydroxyl groups of cellulose form multiple hydrogen bonding interactions and electrostatic attraction interactions, effectively inhibiting the non-radiative transitions. The resultant cellulose-based RTP material is easily processed into phosphorescent films, fibers, coatings and patterns by using eco-friendly aqueous solution processing strategies. Furthermore, after we construct a cross-linking structure by adding a small amount of glutaraldehyde as the cross-linking agent, the as-fabricated phosphorescent patterns exhibit excellent antibacterial properties and water resistance. Therefore, considering the outstanding biodegradability and sustainability of cellulose materials, cellulose-based easy-to-process RTP materials can act as antibacterial, water-resistant, and eco-friendly phosphorescent patterns, coatings and bulk materials, which have enormous potential in advanced anti-counterfeiting, information encryption, disposable smart labels, etc., (© 2022. The Author(s).)

It is practical and challenging to construct ultrasensitive and multi-responsive sensors for visual and real-time monitoring of the environment. Herein, a cellulose-based multi-responsive fluorescent sensor (Phen-MDI-CA) is fabricated, and realizes a visual and ultrasensitive detection of not only various amines but also three anions based on the change of the fluorescence and/or visible colors. Once exposure to various amines in both the solution and vapor state, the Phen-MDI-CA solution and test paper exhibit different fluorescence colors, which can be used to distinguish triethylamine, ethylenediamine, methylamine, aniline, hydrazine and pyrrolidine from other amines. Moreover, via combining the Phen-MDI-CA with the Phen-MDI-CA/malachite green ratiometric system, phosphate (PO 4 3- ), carbonate (CO 3 2- ) and borate (B 4 O 7 2- ) can be visually and accurately recognized depending on the change of the visible and fluorescence colors. In fluorescent mode, the LOD for B 4 O 7 2- , PO 4 3- anions in the mixture of anions. The state-of-the-art responsive behavior of Phen-MDI-CA originates from the amplification effect of cellulose polymer chain and the differentiated interactions between the sensor and analytes.3 2- ions is as low as 0.18 nmol, 0.69 nmol and 0.86 nmol, respectively. Significantly, the Phen-MDI-CA can readily make a qualitative and quantitative detection of B 4 O 7 2- , PO 4 3- and CO 3 2- anions in the mixture of anions. The state-of-the-art responsive behavior of Phen-MDI-CA originates from the amplification effect of cellulose polymer chain and the differentiated interactions between the sensor and analytes., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Herein, a simple, effective, and general strategy is demonstrated to obtain a water-soluble and nontoxic cellulose-based photosensitizer (CPS) with enhanced photodynamic antibacterial activity through introducing protoporphyrin IX (PpIX) and quaternary ammonium salt (QAS) groups onto the cellulose backbone. The synergistic effect of the anchoring and diluting effect of the cellulose backbone and the electrostatic repulsion between QAS groups effectively inhibit the π-π stacking of PpIX groups, thus the as-prepared CPS exhibits markedly enhanced reactive oxygen species (ROS) yield. Meanwhile, the positively charged QAS groups endow the CPS with water-solubility and a strong attractive force to bacteria. As a result, the CPS can rapidly and efficiently kill drug-resistant bacteria strains, including E. coli and S. aureus, with a low light dose (2.4 J cm -2 ) and low concentration of PpIX groups (0.35 × 10 -6 m). Benefiting from the excellent processability and formability, the CPS is readily applied as a sunlight-driven wearable and robust antibacterial coating by a spray coating and later crosslinking procedure., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Herein, we design and prepare cellulose-based ratiometric fluorescent materials with superior amine-response, which offers the real-time and visual detection of seafood freshness. Through utilizing the reactive hydroxyl groups along cellulose chains, we covalently immobilize the fluorescein isothiocyanate (FITC) as indicator and protoporphyrin IX (PpIX) as internal reference onto cellulose acetate (CA), respectively. Subsequently, a series of dual-emission solid fluorescent materials are achieved by simply blending green emitting CA-FITC with red-emitting CA-PpIX with varying ratios. They exhibit a sensitive, color-responsive, rapid and linear response to ammonia in a wide range of 5.0 ppm to 2.5 × 10 4 ppm. Benefiting from the excellent solubility and processibility of cellulose derivatives, the as-prepared materials are readily processed into different material forms, including printing ink, coating, flexible film, and nanofibrous membrane. The electrospun nanofibrous membrane is successfully employed as a low-cost, high-contrasting, quick-responsive fluorescent trademark for visual monitoring the freshness of shrimp and crab.

Excessive radicals and UV irradiation can trigger oxidative and physiological stresses, which cause tissue aging, human disease, food spoilage, and material degradation. In this study, a multifunctional cellulose ester containing hindered phenol groups, cellulose 3,5-di- tert-butyl-4-hydroxybenzoate (CBH), with free-radical-scavenging and UV-resistant activities was synthesized and used as a functional material. The obtained CBHs can effectively scavenge reactive nitrogen free radicals and hydroxyl free radicals in both solid and solution states. Moreover, CBHs have no cytotoxicity, and, on the contrary, they promote the proliferation of human epidermal keratinocytes. Benefiting from excellent solubility, processability, and formability, CBHs have been readily processed into flexible films, transparent coatings, and nanoribbons membranes. The highly transparent and flexible CBH film completely absorbs the light of 200-300 nm range and partially absorbs the light of 300-400 nm range, indicating a UV-shielding capability. After the CBHs were loaded on an ordinary facial mask by electrospinning or added into a hand cream, the resultant facial mask and hand cream exhibited outstanding free-radical-scavenging properties. In addition, CBHs can also be used to fabricate functional sprays with antioxidative and UV-shielding activities. Accordingly, the obtained CBHs have a huge potential in cosmetics, personal care products, biopharmaceuticals, papermaking, and art protection because of their excellent antioxidation, nontoxicity, UV resistance, formability, and odorless properties.

In this study, we successfully extracted cellulose from borassus fruit fibers by chemical process. The extracted cellulose was dissolved in an ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl). Using this solution, regenerated cellulose films were prepared with water as the non solvent. The raw fruit fibers and extracted cellulose were characterized by chemical analysis. The results indicated that the content of the components other than cellulose was significantly decreased during the cellulose extraction process. Further, FTIR, 13 CP-MAS NMR, wide-angle X-ray diffraction (XRD), thermo gravimetric analysis (TGA) and scanning electron microscopy (SEM) were used to provide structural characterization of raw fibers, extracted cellulose and regenerated cellulose films. The average tensile strength, modulus and elongation at break of the regenerated cellulose films were found to be 111±19MPa, 6149±603MPa and 3.1±0.8%, respectively. The notable properties of regenerated cellulose films advocate their effectiveness for various industrial applications., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Waste newspapers, composed of cellulose (>60wt%), lignin (∼15wt%), hemicellulose (∼10wt%) and other additives, are one kind of low-cost, easily collected and abundant resources. In order to get value-added products from this waste, in this work an attempt was made to directly convert waste newspapers into cellulose-based films by employing an ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl) as a solvent. Most of the organic substances in this waste were dissolved quickly in AmimCl under mild conditions, and then coagulated and dried. Although containing lignin, hemicellulose and inorganic additives, the regenerated cellulose-based films were smooth, compact and semi-transparent, and exhibited good mechanical properties. If the newspaper/AmimCl solution was filtered to remove undissolved inorganic substances, the regenerated films became transparent and had a tensile strength of 80MPa. Thus, this work provides a new, simple and highly efficient way to achieve a high-valued utilization of waste newspapers for packaging and wrapping., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

The solubility of eight types of polyhedral oligomeric silsesquioxane (POSS) derivatives in an ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl) and the dispersion of POSS in cellulose matrix were examined. Only a special POSS containing both aminophenyl and nitrophenyl groups (POSS-AN, NH2:NO2=2:6) was selected to prepare nanocomposites, because of its good solubility in AmimCl and high stability during the preparation process. POSS-AN nanoparticles were uniformly dispersed in a cellulose matrix with a size of 30-40nm, and so the resultant cellulose/POSS-AN nanocomposite films were transparent. The mechanical properties of the films achieved a maximum tensile strength of 190MPa after addition of 2wt% POSS-AN. Interestingly, all of the cellulose/POSS-AN films exhibited high UV-absorbing capability. For the 15wt% cellulose/POSS-AN film, the transmittance of UVA (315-400nm) and UVB (280-315nm) was only 9.1% and nearly 0, respectively. The UV aging and shielding experiments showed that the transparent cellulose/POSS-AN nanocomposite films possessed anti-UV aging and UV shielding properties., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

The applications of natural fibers and their microfibrils are increasing rapidly due to their environment benefits, specific strength properties and renewability. In the present work, we successfully extracted cellulose microfibrils from Agave natural fibers by chemical method. The extracted microfibrils were characterized by chemical analysis. The cellulose microfibrils were found to dissolve in an ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl) to larger extent along with little quantity of undissolved microfibrils. Using this solution, the self-reinforced regenerated cellulose composite films were prepared. The raw fiber, extracted cellulose microfibrils and regenerated cellulose composite films were characterized by FTIR, (13)C CP-MAS NMR, XRD, TGA and SEM techniques. The average tensile strength, modulus and elongation at break of the self-reinforced cellulose composite films were found to be 135 MPa, 8150 MPa and 3.2%, respectively. The high values of tensile strength and modulus were attributed to the self-reinforcement of Agave fibers in their generated matrix. These self-reinforced cellulose biodegradable composite films prepared from renewable source can find applications in packaging field., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Using 4-dimethylaminopyridine (DMAP) as the catalyst, highly efficient propionylation and butyralation of cellulose were successfully carried out in an ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl) under mild conditions. Cellulose propionate (CP) and cellulose butyrate (CB) with a degree of substitution (DS) in the range from 0.89 to 2.89 were synthesized within only 30 min at 30 °C. The DS values of the products could be well controlled just by molar ratio of acid anhydride/anhydroglucose unit (AGU). More interestingly, the conversions of acid anhydrides in both propionylation and butyralation were as high as above 90%, even 96%. Therefore, this work provides a facile and highly efficient way for the synthesis of cellulose esters CP and CB., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Taking advantage of the negligible vapor pressure and dissolving features of ionic liquids (ILs), the solution morphology and dissolution process of cellulose in ILs have been visualized directly by conventional transmission electron microscopy (TEM) at room temperature for the first time.

An effective method for grafting L-lactide (LA) from unmodified cellulose by ring-opening polymerization (ROP) in homogeneous mild conditions is presented. By using 4-dimethylaminopyridine (DMAP) as an organic catalyst, cellulose-graft-poly(L-lactide) (cellulose-g-PLLA) copolymers with a molar substitution (MS(PLLA)) of PLLA in a range of 0.99-12.28 were successfully synthesized in ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl) at 80 degrees C. The amount and length of grafted PLLA in cellulose-g-PLLA copolymers were controlled by adjusting the molar ratios of LA monomer to cellulose. The structure and thermal properties of cellulose-g-PLLA copolymers were characterized by (1)H NMR, (13)C NMR, wide-angle X-ray powder diffraction (WAXD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and optical microscopy. The DSC results revealed that the copolymers exhibited a single glass transition temperature, T(g), which sharply decreased with the increase of MS(PLLA) up to MS(PLLA) = 8.28 (DS(PLLA) = 2.19) and increased a little with a further increase of the lactyl content. When MS(PLLA) was above 4.40, the graft copolymers exhibited thermoplastic behavior, indicating the intermolecular and intramolecular hydrogen bonds in cellulose molecules had been effectively destroyed. By using a conventional thermal processing method, fibers and disks of cellulose-g-PLLA copolymers were prepared.

Cellulose is hierarchically arranged to form a sophisticated supramolecular structure. The structural complexity leads to a dilemma where the intrinsic luminescence properties of cellulose itself have not been well understood. In this study, crystalline and amorphous cellulose from tunicate was prepared to investigate the nonconventional photoluminescence property. In cellulose, the crystalline regions are in the form of cellulose nanocrystals (CNCs). After extraction from the original fibers, the CNCs are used in foams, in films made only of CNCs, and also in CNC/PVA films. In those different systems, there are different hydrogen bonding interactions among the hydroxy groups on the CNC surfaces. CNC foam has the strongest fluorescence emission intensity with the highest photoluminescence quantum yield (PLQY 10.94%), but lowest phosphorescence intensity with the shortest phosphorescence lifetime of 178.77 ms. The CNC/PVA films, on the other hand, have the lowest PLQY (5.15%) and longest phosphorescence lifetime (569.38 ms). The results indicate that hydrogen bonding interaction effectively inhibits the motion of hydroxyl groups on the surface of CNCs, which is favor for stronger phosphorescence emission and longer phosphorescence lifetime. Compared with the crystalline cellulose (pulp film), the highly amorphous cellulose (ReAC-Pulp film) exhibits stronger phosphorescence emission intensity and longer lifetime (808.33 ms), with the maximum emission wavelength significantly blue-shifted from 494 nm to 461 nm. This is attributed to the different intra- and intermolecular hydrogen bonding networks of amorphous cellulose and the lack of surface group motion on the nanocrystals. This hydrogen-bond assisted luminescence property may contribute to reveal the complicated supramolecular structure of cellulose materials. [ABSTRACT FROM AUTHOR]

Disposable paper cups are widely used in daily life and most of them are landfilled or incinerated after use, resulting in a serious ecological hazard and significant waste of resources due to the usage of thin polyethylene (PE) as their inner coating. Hence, converting these common solid domestic wastes into high-value added materials is attractive and meaningful. In this study, transparent cellulose-based films were achieved from old bamboo-based disposable paper cups after pretreatment through using the room ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl) as solvent. The cellulose-based film with a dense texture demonstrated a relatively nice mechanical and UV-shielding performances, and its tensile strength was as high as 48 MPa, much higher than that of commercial polyethylene (PE, 12 MPa) film. Thus, the resultant cellulose-based film showed a great potential in the packaging field. Besides, the flexible paper plastic composites (PPC) were also fabricated from the rest thin PE coating with the stuck fibers, and it was found that PPC showed excellent mechanical property and hydrophobicity. Consequently, a feasible and eco-friendly process of recycling and reusing waste disposable paper cups was developed to achieve a complete utilization and valorization of waste disposable paper cups. [ABSTRACT FROM AUTHOR]

Disposable paper cups are usually composed of high-grade paper board and an inner polyethylene coatings and are extensively used in daily life. However, most disposable paper cups are only used for a short time and then incinerated or accumulated in landfill at the end of their service due to the difficulty in separating the components, leading to a serious threat to our ecosystem. Therefore, developing a facile and green method to recycle and reuse disposable paper cups is vital. By using ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl) as a solvent, transparent and homogenous cellulose/polyethylene composite films were successfully prepared from used bamboo-based disposable paper cups through the "one-pot method", without any pre-treatment. It was found that there was a transformation of cellulose I to II after the dissolution and regeneration processes, and the crystallinity degree of the regenerated cellulose-based materials decreased significantly, resulting in a change in thermal properties. Meanwhile, compared to traditional pure cellulose films, the composite films possessed good UV-shielding properties and hydrophobicity. Moreover, they also displayed good mechanical properties. Additionally, the size of the ground PE coatings displayed obvious effects on the structures and properties of the composite films, where the CPE100 (sieved with 100–200 mesh) possessed the most homogeneous texture and the highest tensile strength (82 Mpa), higher than that of commercial polyethylene film (9–12 MPa), showing superiority as packaging or wrapping materials. Consequently, the goals to fabricate uniform cellulose/polyethylene composite films and valorize the solid waste from disposable paper cups were simultaneously achieved by a facile and green "one-pot method". [ABSTRACT FROM AUTHOR]

CO2 gas separation is of significant importance to protect the environment and utilize the carbon resource. In this work, two kinds of new cellulose esters containing imidazolium cation, cellulose acetate (CA) 1‐butyl‐3‐methylimidazolium chloride and CA 1‐butyl‐3‐methylimidazolium bis(trifluoromethane sulfonyl)imide (CA‐BmimTf2N), are designed and synthesized. The resultant cationized cellulose esters effectively lock various ionic liquids (ILs) via electrostatic interactions. Due to the strong attraction interactions, the obtained cellulose ester/ILs composite membranes are uniform, smooth, and highly transparent. Moreover, the added ILs with a long alkyl chain in the cation and a bis(trifluoromethane sulfonyl)imide anion remarkably improve the CO2 permeability of the cellulose ester/ILs membranes, because of the dramatic increase of the CO2 diffusion rate. The CA‐BmimTf2N/C10mimTf2N membranes exhibit the highest CO2 permeability, which is 3800% higher than that of CA membrane and 1700% higher than that of CA‐BmimTf2N membrane. More importantly, the CA‐BmimTf2N/C10mimTf2N membranes have good mechanical properties and thermal stability. Such high‐performance CO2 separation membranes with high CO2 permeability, high transparency, and good mechanical property have a huge potential in the practical utilization for gas separation. [ABSTRACT FROM AUTHOR]

It is challenging to design and fabricate new and high-performance cellulose-based chiral stationary phases (CSPs), due to the indistinct chiral recognition mechanism and the inherent difficulty to control the structure of cellulose derivatives. Herein, taking advantage of the high regioselective benzoylation of cellulose in 1-allyl-3-methylimidazolium chloride, a series of regioselectively substituted cellulose mixed esters, cellulose 6-benzoate-2,3-phenylcarbamate, are directly obtained by a facile two-steps route without protecting and deprotecting process. The resultant cellulose mixed esters exhibit high chiral recognition capability. In particular, when the benzoate group has an electron-donating substituent on phenyl ring, such as 4-tert-butyl group, the corresponding regioselectively substituted cellulose mixed esters have much better enantioseparation capability than cellulose tri(3,5-dimethylphenylcarbamate), which is commercially available as Chiralcel OD column, one of the most powerful CSPs. More importantly, via adjusting the chemical structure of cellulose derivatives and adding a post-treatment process to optimize their chiral recognition properties, the chiral recognition mechanism is clearly revealed. The synergy of the hydrophobic helical conformation, weak hydrogen-bond donating ability and appropriate distribution of substituents of cellulose derivatives is essential to fabricate high-performance CSPs. Regioselectively substituted cellulose mixed esters with super chiral separation capability are directly synthesized by a facile two-steps process. The synergism of the hydrophobic helical conformation, weak hydrogen-bond donating ability and appropriate distribution of substituents in cellulose derivatives is essential to the enantioseparation. Image 1 • Regioselectively substituted cellulose mixed esters are got by a two-steps process. • Cellulose mixed esters exhibit super chiral recognition capability. • Chiral recognition mechanism is revealed. [ABSTRACT FROM AUTHOR]

Novel cellulose nanomicelles self-assembled from amphiphilic cellulose-graft-poly( p-dioxanone) (MCC- graft-PPDO) copolymer were used to encapsulate and disperse hydrophobic fluorescent conjugated polymers (FCPs) in water for tumor cell imaging. Three different conjugated polymers were employed to demonstrate the versatility of the cellulose nanomicelles, resulting in highly fluorescent and stable polymeric nanoparticles with different emission wavelengths across the visible spectrum. Owing to the size effect of cellulose nanomicelles, the incorporated conjugated polymers present red-shifted emission to low-energy sites, and the fluorescence self-quenching of conjugated polymers at high concentration can be greatly inhibited. The in vitro studies using the liver cancer Hep3B cells and the breast cancer MAD-MB-231 cells indicate these amphiphilic cellulose/FCPs nanomicelles have negligible cytotoxicity even at high concentration of up to 100 μg/mL. Moreover, the light-emitting micelles are successfully uptaken by the cancer cells and located at the cytoplasm of the cells, suggesting their great potential for tumor cell imaging and early detection of tumor cells. [ABSTRACT FROM AUTHOR]

Organic solid-state fluorescent materials have exhibited great potential application in optoelectronics, imaging, sensing, and security printing. However, the conventional conjugated luminogens such as perylene and pyrene derivatives are not highly recommended for preparation of the solid fluorescent materials because they always undergo fluorescence self-quenching in solid state, i.e., aggregation caused quenching (ACQ) phenomenon. Herein, a series of solid materials with excellent fluorescent emission have been realized via covalently bonding the ACQ luminogens onto the cellulose chains and subsequently ionizing process. The synergy between the anchoring and diluting effect on luminogens of cellulose skeleton and the electrostatic repulsion among the ACQ luminogens efficiently inhibits the aggregation and the self-quenching of luminogens. Such a general strategy is suitable for different ACQ luminogens and various partially substituted cellulose derivatives. Furthermore, the prepared fluorescent solids preserve the excellent properties of original cellulose derivatives such as good solubility and processibility. Therefore, they can be readily processed into materials in different forms, including printing pattern, coating, film, fiber, colloid, etc. This simple and effective strategy gives added impetus to the applications of solid fluorescent materials in practice. [ABSTRACT FROM AUTHOR]

Using 1-allyl-3-methylimidazolium chloride (AmimCl) as the solvent, cellulose/microalgae (C/M) composite films with microalgae content ranging from 19.14 to 78.83 wt% were prepared by solution-mixing and subsequent casting. The structure and properties were characterized by element analysis, Fourier transform infrared (FTIR) spectra, scanning electron microscopy (SEM), thermogravimetry, tensile test, hydrolytic degradation, and cell cultivation test. SEM and FTIR results indicated good compatibility between the microalgae and cellulose due to strong hydrogen bonding interaction. These composite films possessed good mechanical properties and thermal stability that are better than those of other microalgae based materials. The hydrolytic degradation rate of C/M composite films with microalgae content higher than 33.97% was faster than cellulose, and increased significantly with the increase of microalgae content. The cell culture experiments confirmed that the C/M composite films could support cell adhesion and proliferation, consequently exhibit good biocompatibility. Therefore, the C/M composite films can be considered as novel functional films with applications as biodegradable materials even in medical fields. [ABSTRACT FROM AUTHOR]

Homogeneous carbanilation of cellulose with nine kinds of substituted phenyl isocyanates, in which the substituents were varied from electron-donating to electron-withdrawing groups, was carried out in 1-allyl-3-methylimidazolium chloride (AmimCl) without any catalyst. The degree of substitution (DS) of cellulose phenylcarbamates in a range from 0 to 3 was readily controlled by altering reaction temperature, reaction time andmolar ratio of phenyl isocyanate/anhydroglucose unit. Furthermore, the electronic effect of the substituents on the aromatic ring had a prominent impact on the reactivity of phenyl isocyanates. The phenyl isocyanates with stronger electron-withdrawing substituents exhibited a higher reactivity. A plot of DS and Hammett substituent constants exhibited linearity with a positive slope. Subsequently, four kinds of partially substituted cellulose phenylcarbamates with DS of 2.0 were synthesized successfully in AmimCl, and then employed as coated-type chiral stationary phases (CSPs) for high-performance liquid chromatography. The enantioseparation results demonstrated that these CSPs exhibited high chiral recognition abilities for some racemates. The substituents on the phenyl moieties had a considerable effect on the chiral recognition ability of cellulose phenylcarbamate-based CSPs. [ABSTRACT FROM AUTHOR]

Homogeneous esterification of cellulose, which can control themolecular structure of the resultant cellulose esters and facilitate the versatility of cellulose-based materials, has drawn much attention. Recently, the advent of room temperature ionic liquids (ILs) capable of dissolving cellulose hasprovided anewandversatile platform for theefficient andhomogeneousesterification of cellulose. A variety of conventional, novel and functional cellulose esters have been successfully synthesized in ILs. Mean while, development of esterification techniques, utilization of agricultural residues and up-scaling of pilot schemes of esterification in ILs have been in progress. This review summarizes the advances and developments in homogeneous synthesis of cellulose esters in ILs in recent decades. [ABSTRACT FROM AUTHOR]

Cellulose derivatives containing adamantane groups are homogeneously synthesized by a simple, rapid and environmentally friendly way using 1-allyl-3-methylimidazolium chloride (AmimCl) ionic liquid as reaction media. Without any catalysts, cellulose adamantates (CAd) with degree of substitution (DS) in a range from 0.71 to 2.25 are prepared just in one-step. In addition, a series of mixed esters, cellulose adamantate acetate (CAdAc), are also synthesized via the “one-pot” process. The obtained CAd and CAdAc are characterized by means of FT-IR, NMR, XRD, DSC and TGA. Meanwhile, their gas permeabilities of these materials for O 2 , N 2 , CH 4 , CO and CO 2 are studied. CAd exhibits improved solubility in organic solvents, low glass transition temperature and good thermostability. In particular, the free-volume topology of CAd membranes has been tailored by controlling the DS of adamantane, thus CAd membranes display a significant enhancement for gas permeability with good ideal permselectivity for several gas pairs, such as O 2 /N 2 , CO 2 /N 2 , CO 2 /CH 4 and CO 2 /CO. For CAdAc, introducing only a small amount of adamantane groups in cellulose acetate could achieve better gas permeability and similar or slightly lower ideal permselectivity. [ABSTRACT FROM AUTHOR]

Paper cups are widely employed in daily life with many advantages, but most of the used paper cups are incinerated or landfilled, due to the great challenge of separating the thin inner polyethylene (PE) coating, causing the waste of energy and the pollution of our environment. Therefore, recycling and converting the used paper cups into high-value materials is meaningful and important. In this work, transparent cellulose-based films were successfully prepared from the used paper cups via 1-allyl-3-methylimidazolium chloride ionic liquid after simple pretreatment. Additionally, the difference in properties and structures of cellulose-based films regenerated in different coagulation baths (water or ethanol) was also explored. It was found that the cellulose-based film possessed good thermal property and displayed better hydrophobicity than the traditional pure cellulose film. Moreover, they also demonstrated good mechanical property and the tensile strength of cellulose-based film regenerated in water can reach 31.5 Mpa, higher than those of cellulose-based film regenerated in ethanol (25.5 Mpa) and non-degradable polyethylene film (9–12 MPa), indicating their great potential as the packaging materials. Consequently, valorization of the low cost used paper cups and preparation of high-valve cellulose-based films were realized simultaneously by a facile and green process. [ABSTRACT FROM AUTHOR]

Using native cellulose as the starting material, cellulose acetate- graft-ploy ( l-lactide) (CA- g-PLA) copolymers were successfully synthesized by 'one-pot' process in an ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl). In this process, cellulose was first reacted with acetic anhydride, yielding cellulose acetate (CA), and then ring opening graft copolymerization of l-lactide was carried out from the residual hydroxyl groups of CA in the same solution using 4-dimethylaminopridine (DMAP) as the catalyst. Both acetyl and ploy ( l-lactide) contents in CA- g-PLA copolymers could be well controlled by changing reaction conditions. The structures and thermal properties of CA- g-PLA copolymers were characterized. The glass transition temperature T of copolymers decreased with increasing PLA content. Compared to the pure PLA and cellulose- graft-PLA copolymers, the CA- g-PLA copolymers possessed better thermo mechanical properties in a temperature range of 60-130 °C. When the molar substitution of PLA (MS) was above 1.71, the CA- g-PLA copolymers exhibited thermoplastic behavior and could be processed by conventional thermal processing methods, such as injection molding and melt spinning. [ABSTRACT FROM AUTHOR]

The ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl) as a reaction medium was studied for the synthesis of cellulose benzoates by homogeneous acylation of dissolved cellulose with benzoyl chlorides in the absence of any catalysts. Cellulose benzoates with a degree of substitution (DS) in the range from about 1 to 3.0 were accessible under mild conditions. The DS of cellulose derivatives increased with the increase of the molar ratio of benzoyl chloride/anhydroglucose unit (AGU) in cellulose, reaction time, and reaction temperature. Benzoylation of cellulose with some 4-substituted benzoyl chlorides including 4-toluoyl chloride, 4-chlorobenzoyl chloride and 4-nitrobenzoyl chloride was also readily carried out under mild conditions. Furthermore, regioselectively substituted mixed cellulose esters were synthesized in this work. All products were characterized by means of FT-IR, 1H-NMR, and 13C-NMR spectroscopy. In addition, at the end of benzoylation of cellulose, the ionic liquid AmimCl was easily recycled. When the recycled AmimCl was used as the reaction media, the cellulose benzoate with a similar DS was obtained under comparable reaction conditions. [ABSTRACT FROM AUTHOR]

Waste polyester-cotton blended textiles have huge production and most of them are incinerated and landfilled, leading to seriously environmental pollution and significant waste of natural resources. Hence, recycling these textile wastes to other value-added products in a sustainable and economical way is meaningful and urgent. In order to completely utilize and valorize polyester-cotton blended textiles, transparent regenerated cellulose films and high-purity recovered polyethylene terephthalate (PET) film were successfully prepared via ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl). It is indicated that cotton fibers in waste polyester-cotton blended fabrics can be fully dissolved in AmimCl, resulting in efficient separation of polyester and cotton. The transparent cellulose films can be achieved after coagulating and drying processes. Moreover, the changes in morphology and crystalline structure of cellulose films regenerated in different coagulation bath were also investigated in detail, in which cellulose films with dense structure regenerated from water coagulation bath exhibited good mechanical properties and tensile strength was as high as 35 MPa, much higher than that of polyethylene (PE, 9 MPa) self-sealing bag membrane commonly used in laboratory, showing great potential application in packaging and wrapping fields. Meanwhile, the high purity PET residue was also reused as raw material to fabricate transparent and flexible PET film by melt pressing, whose tensile strength can reach 36 MPa. Consequently, a facile and eco-friendly process of recycling and reusing polyester-cotton blended textiles was developed and the high-valued utilization of waste polyester-cotton blended textiles can also be realized. [Display omitted] • Waste polyester-cotton blended textiles could be recycled and reused via AmimCl. • Regenerated cellulose films were obtained after dissolution and regeneration. • The obtained regenerated cellulose films exhibited good mechanical properties. • Recovered polyethylene terephthalate (PET) film can be achieved by melt pressing. • The achieved PET film displayed good transparency and flexibility. [ABSTRACT FROM AUTHOR]

We designed and demonstrated a cellulose-based, transparent and multifunctional coating with excellent anti-fogging, anti-icing, anti-bacterial, water-resistant, self-cleaning and anti-bioadhesion properties. [Display omitted] • A single-component coating spontaneously manages the water aggregation morphology. • The synergism of weak hygroscopicity and high hydrophobicity is essential. • A multifunctional coating with superior anti-fogging, anti-icing, and self-cleaning properties. Fogging and icing are common phenomena in nature, but they bring huge harm in the human life and production, such as the deterioration of optical devices, the detriment of vehicles operating, the destruction of power transmission lines. In this work, we designed and constructed a cationic cellulose derivative with both weak hygroscopicity and high hydrophobicity to achieve a spontaneous management of the aggregation morphology of interfacial water, via precisely controlling the chemical structure of cellulose derivatives. As a result, the resultant cationic cellulose derivative can be used as a transparent and water-resistant coating, which exhibits universal anti-fogging, excellent anti-icing and anti-bioadhesive properties. Under low humidity, the coating can effectively absorb water to form a pseudo-film due to the ionized structure and retained hydroxyl groups. Under high humidity, the coating can promote water droplets to roll off due to the high hydrophobicity. The coating with weak hygroscopic core and high hydrophobic surface thus has a universal anti-fogging performance. In addition, this ionized coating with weak hygroscopicity can adjust the interfacial water performance, so it can reduce the freezing temperature of water to −30 ℃, and the ice adhesion stress to 10 kPa at −30 ℃. The freezing time of water exceeds 2 h at −25 ℃. Furthermore, the bacterial killing percentage on this coating is more than 97 % for Staphylococcus aureus. Due to high hydrophobicity and low surface energy, this coating has outstanding water-resistance, self-cleaning property, anti-chlorella adhesion and anti-protein adhesion. Therefore, such a multifunctional coating prepared by a simple structure design from natural cellulose has a great potential in display devices, traffics, solar products, wind generator, agricultural greenhouse, and other fields. [ABSTRACT FROM AUTHOR]

A series of cellulose- g -poly( l -lactide) (cellulose-g-PLLA) copolymers with 30.65–85.21 % PLLA weight content and the molar substitution of PLLA (MS PLLA ) from 0.99 to 12.73 were synthesized via the homogeneous graft-from reaction in 1-allyl-3-methylimidazolium chloride (AmimCl) with 4-dimethylaminopyridine (DMAP) acting as the catalyst. In common organic solvents, the solubility of obtained graft copolymers was better than cellulose and strongly depended on the MS PLLA . The hydrolytic degradation of cellulose- g -PLLA copolymers was investigated in phosphate buffered solution (PBS, pH 7.4) at 37 °C. Interestingly, it was found that, when the MS PLLA was below 8.83, the hydrolytic degradation rate of cellulose- g -PLLA copolymers was obviously faster than that of both pristine cellulose and PLLA. Moreover, as the MS PLLA decreased, the cellulose- g -PLLA copolymers showed a more rapid weight loss, due to its higher hydrophilicity. Both XPS and 1 H NMR analyses demonstrated the degradation occurred mainly at PLLA segments. The morphological observations indicated that, during the hydrolytic degradation, the graft copolymers firstly experienced a surface erosion process, and then the bulk erosion happened. [ABSTRACT FROM AUTHOR]

Over the past few years, cellulose nanosphere (CNS) has gained growing attention and rapid development. As a new type of nanocellulose materials, CNS can be prepared from native cellulose by using methods which have been adopted extensively to prepare the well-known nanocelluloses, i.e., cellulose nanofiber and cellulose nanocrystal. The particular interest is that the regenerated cellulose and mercerized cellulose can also be used as important feedstocks to produce CNS. In this review, the preparation methods of CNS are described and discussed, via both top-down processes, including chemical, mechanical, and enzymolysis ones, and bottom-up processes by using various cellulose I and II starting materials. This review also highlights the researches relative to cellulose composite nanospheres, and summarizes the applications of spherical cellulose-based nanoparticles. Finally, the future challenges and opportunities of CNS are prospected in this work. • A novel nanocellulose material, cellulose nanospheres, is reviewed. • The preparation of the spherical nanocellulose via top-down and bottom-up processes are presented. • The application of cellulose and cellulose composite nanospheres are also included. [ABSTRACT FROM AUTHOR]

Abstract: Rheological properties of cellulose dissolved in two ionic liquids (ILs), 1-allyl-3-methylimidazolium chloride (AmimCl) and 1-butyl-3-methylimidazolium chloride (BmimCl), with co-solvent dimethylsulfoxide (DMSO), are studied in the concentration range of cellulose from 0.070 to 6.0 wt%. The viscosities of ILs are exponentially decreased by adding DMSO in the concentration range of 0–100 wt%. The co-solvent DMSO decreases the monomer friction coefficient in cellulose solutions and has no significant change for the entanglement state of cellulose, thus results in the reduced solution viscosity, shortened relaxation time and unchanged moduli of the cross-over point. For cellulose solutions, dilute regime, semidilute unentangled regime and semidilute entangled regime were determined by steady shear experiments. In semidilute entangled regime, the specific viscosities η sp, relaxation time τ, and plateau modulus G N, exhibit concentration dependences as η sp ∼ C 4.4, τ ∼ C 2.2, andG N ∼ C 1.9, respectively, in AmimCl-DMSO (80/20 w/w); and η sp ∼ C 4.3, τ ∼ C 2.0, and G N ∼ C 2.1, respectively, in BmimCl–DMSO (80/20 w/w). Therefore, the rheological properties of cellulose/IL/DMSO solutions are approximately of IL-independence in this study. The dependence of η sp upon cellulose concentration shows that the IL–DMSO mixture is more like a θ solvent for cellulose, and the thermodynamic properties of IL–DMSO mixtures are similar with those of ILs for cellulose at 25 °C. The conformation of cellulose in ILs would not be changed with the addition of DMSO not only in the dilute regime but also in the entanglement regime. [Copyright &y& Elsevier]

Cellulose, the most abundant natural polymer on the planet, is the major polysaccharide produced by plant photosynthesis. It has many advantages, such as renewability, tremendous reversibility, complete biodegradability, excellent biocompatibility, high mechanical property and structural designability. The molecular weight and polydispersity index are the key parameters of cellulose materials. Measurement of the molecular weight characteristics of cellulose is of great significance for effectively utilizing cellulose resources and comprehensively understanding the relationship between structure and property. In this review, we summarize the methods used to characterize the molecular weight of cellulose and focus on the detailed applications of ionic liquids for such characterization. • A review summarized the characterization of the molecular weight of cellulose. • The application of ionic liquids to characterize cellulose was discussed. • It is vital to determine the molecular weight parameters of cellulose. [ABSTRACT FROM AUTHOR]

• A robust strategy is proposed to convert cellulose into functional coating. • Inherently flame-retardant, anti-dripping and easy-to-process coating is obtained. • Cellulose-based flame-retardant protecting coating is constructed. The inherent high flammability and poor processability characteristics of cellulosic materials result in dominant adverse impacts on their practical applications. Here, we proposed a robust strategy for converting highly flammable cellulose into an inherently flame-retardant, halogen-free, anti-dripping and easy-to-process material, DOPO-cellulose acrylate (DCA), by controllably introducing acrylate groups into cellulose chains and later covalently immobilizing 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) through an addition reaction between acrylate groups and DOPO. A small number of DOPO groups in DCA significantly reduce the heat release rate and total heat release, and promote the formation of dense and continuous char. Thus, the free-standing and transparent films of the resultant DCA self-extinguish instantly (<1 s) once removed from the flame. Meanwhile, partial acrylate groups are deliberately retained to obtain UV light-crosslinkable DCA, which can form a rigid three-dimensional cross-linked network, thereby inhibiting melt dripping. Benefitting from the excellent formability, the UV light-crosslinkable DCA can easily be processed into flame-retardant, anti-dripping and transparent coatings for protecting various flammable materials from fire, such as paper and wood. The present inherently flame-retardant cellulosic materials show promise for use as novel functional bulk materials and coatings to protect books, buildings and furniture. [ABSTRACT FROM AUTHOR]

Herein, a striking anion-tunnel transfer effect was demonstrated in 1-butyl-3-methylimidazolium benzoate (BmimPhCOO) ionic liquid, so a rapid, mild and efficient benzoylation of cellulose is accomplished under catalyst-free condition in BmimPhCOO. In a wide temperature range of 20–80 °C, the equilibrium of reaction is reached within only 15 min, which is much faster than the reported acylation of cellulose. Furthermore, the resultant cellulose tribenzoates have excellent solubility in conventional organic solvents, thus they can be used to accurately reflect the molecular weight and dispersity index of cellulose raw materials by gel permeation chromatography. This method is suitable for various cellulose. Therefore, we found a new principle to realize the extremely-rapid acylation of cellulose, and proposed an effective approach to accurately determine the molecular weight parameters of cellulose. A new principle to realize the rapid acylation of cellulose was found to establish an effective strategy for accurately characterizing the molecular weight parameters of cellulose. [Display omitted] [ABSTRACT FROM AUTHOR]

Cellulose films with biodegradability and intrinsically antistatic property have many applications. However, conventional cellulose films show poor toughness and UV-shielding property, and the major sources are high-grade cotton linter or wood pulp. Herein, by using low-cost waste cotton textiles as the raw materials, we successfully fabricated transparent cellulose/aramid nanofibers (ANFs) films, in which in-situ retained ANFs had a diameter of 20–30 nm and a length of several micrometers. Because ANFs and cellulose chains formed strong hydrogen bonding interactions, the tensile strength and elongation of the resultant cellulose/ANFs film with 1.0 wt% ANFs could reach 54.4 MPa and 15.8%, respectively, increased by 63.4% and 154% compared to those of pure cellulose film (33.3 MPa and 6.2%). Meanwhile, the cellulose/ANFs films show excellent UV-shielding properties and irradiation stability. Hence, the novel cellulose/ANFs films with improved mechanical and UV-shielding performance were in-situ prepared leading to enhance the valorization of waste cotton textiles. • Valorization of waste cotton textiles were realized via an eco-friendly process. • Transparent cellulose/aramid nanofibers films were in-situ fabricated successfully. • The obtained cellulose/ANFs films exhibited good mechanical property. • Cellulose/ANFs films displayed excellent ultraviolet shielding performance. [ABSTRACT FROM AUTHOR]

• A new strategy was proposed to produce multi-colored solid-state carbon dots. • The product exhibited photo-triggering, reversible and dynamic-optical properties. • Photo-rewritable paper and dynamic anti-counterfeit patterns were fabricated. Dynamic optical materials can respond to external stimuli to give intriguing and chameleon-like visual effect and carry more information, they hence have attracted considerable attention. In this work, we propose a simple and efficient strategy to construct multi-color solid-state carbon dots (CDs) materials with photo-switchable and reversible dynamic-optical properties. A photochromic and positively-charged cellulose derivative C-Im+-SP with an imidazole salt (Im+) group and a spiropyran (SP) group is designed and synthesized. Subsequently, C-Im+-SP is spontaneously coated on the surface of negatively-charged CDs (NCDs) via electrostatic attraction to form a physical protective shell, which not only inhibits aggregation-caused quenching (ACQ) in NCDs but also promotes effective fluorescence resonance energy transfer (FRET). The resultant NCDs@C-Im+-SP exhibits a photo-triggering reversible dynamic-optical property. The NCDs to C-Im+-SP ratio can be used to effectively regulate fluorescence emission and fluorescence kinetics. The polymeric C-Im+-SP shell layer endows NCDs with excellent processability and formability, whereby NCDs@C-Im+-SP materials can be utilized as functional coatings and inks to fabricate photo-rewritable paper and dynamic anti-counterfeit patterns that have considerable potential applications for special coatings, complex anti-counterfeiting, and information encryption. [ABSTRACT FROM AUTHOR]