Properties and Anti-Ultraviolet Activity of Gallic Acid-Chitosan-Gelatin Mixed Gel

Hydrogel has high water content and structural similarity with natural extracellular matrix.So it has been widely studied and applied in the field of biomedicine.In order to further develop multifunctional hydrogels,we prepared mixed gels with antiultraviolet properties.This study found that the addition of polysaccharides and polyphenols was beneficial to the rheological,me-chanical properties,and biological activity of the protein.Chitosan(CS)could significantly improve the viscoelasticity,hardness,gel strength,thermal stability and crystallinity of gelatin.Interestingly,the addition of gallic acid(GA)could not only provide significant cross-linking effect,improve gel properties and microstructure,but also improve the UV resistance of the mixed gel.

Synthesis of an AVB@ZnTi-LDH composite with synergistically enhance UV blocking activity and high stability for potential application in sunscreen formulations

1-(4-(1,1-Dimethylethyl)phenyl)-3-(4-methoxyphenyl)-1,3-propanedione(known as Avobenzone/AVB),widely used throughout the world as a highly effective UVA absorber,can prevent the progression of photoaging in skin,and is also known for the disadvantage of having a reduced capability to absorb UVA when exposed to sunlight for long periods.To address this challenge,ZnTi-CO_(3)-LDH with a twodimensional layered structure was used to improve stability and synergistically enhance UV absorption of AVB.A novel AVB loaded ZnTi-CO_(3)-LDH(AVB@ZnTi-LDH)material was synthesized by reconstruction method and the loading content(LC)was about 46.8%investigated by high-performance liquid chromatography(HPLC).A possible mechanism for the binding of AVB with the ZnTi-LDH surface was proposed.X-ray photoelectron spectroscopy(XPS)and density functional theory(DFT)calculations were used to confirm further the coordination between Zn on the layer and the oxygen atom of the carbonyl group of AVB.UV absorption and critical wavelength of AVB@ZnTi-LDH were superior to those of AVB and ZnTiLDH precursors.Compared with pure AVB,the photodegradation rate was reduced from 15.06%to 4.06%.Especially in titanium dioxide,the decomposition rate was reduced from 29.75%to 7.92%.Furthermore,pure AVB often reacts with multivalent metal ions to induce an unpleasant color(light yellow to reddish brown),which is greatly mitigated with AVB@ZnTi-LDH.In this study,avobenzone was combined with hydrotalcite to prepare an organic-inorganic composite with excellent UV resistance and better stability,the composite has great promise for application in sunscreen cosmetics.

A core-shell composite pigment with rutile TiO_(2) intensification for UV inhibition

Organic pigments generlly have bright colors but poor ultraviolet(UV)resistance.To improve the UV for UVinhibition is proposed by afacile sol-gel method inthis work.Acore-shellstructure,witha homo resistance and extend the applications,a core-shell composite pigment with rutile Tio intensification geneous sol-gel TiO_(2) shell containing additional nanosized rutile TiO2 particles and with the pigment as the core,was established taking advantage of UV resistance of TiO2 and binding ability of sol-gel.While the sol-gel TiO2 shell alone has already shown obvious ultraviolet shielding effect,as tested over different sol-gel aging times and Tio2 loadings,the UV resistance of the fluorescent pigments was further enhanced by binding the nanosized rutile TiO2 in the sol-gel shell At a sol-gel TiO2 to rutile TiO2 ratio of 2:1,the UV exposure time is extended about eight times compared with that of the original pigment and twice as that of the modifed pigment with pure sol-gel TiO2 for the same color change.Therefore,the novel core-shell composite pigment intensified with nanosized rutile Tio2 particles is proved to be effcient in improving the uV resistance of organic pigments.

Fluorine-containing polyimide nanofiber membranes for durable and anti-aging daytime radiative cooling

Personal daytime radiative cooling(PDRC)materials have high sunlight reflection and high selective emis-sivity to outer space in the main atmospheric window,demonstrating huge potential in energy-saving for sustainable development.Recently,polymer-based membranes for radiative cooling have been widely re-ported,due to their easy processing,low cost,and unique optical performance.However,the desired high sunlight reflectance of PDRC materials is easily dampened by environmental aging,high temperature,and ultraviolet(UV)irradiation,resulting in reduced cooling performance for most polymers,adverse to large-scale practical applications.In this work,we demonstrate a novel polyimide nanofiber(PINF)membrane with a fluorine-containing structure via typical electrospinning technology.The resultant PINF membrane exhibits high sunlight reflectance,UV resistance,and excellent thermal stability,rendering anti-aging day-time radiative cooling.The sunlight reflectance of PINF membranes could maintain constant in the aging test for continuous 720 h under outdoor solar irradiation,exhibiting durable and long-term personal day-time radiative cooling performance.

Application of epoxy resin in cultural relics protection

Cultural relics have their unique artistic, cultural and historical value, and the protection of important cultural relics is conducive to the inheritance of historical culture. As a kind of cementing agent and binder commonly seen in cultural relics protection, epoxy resin is widely used in the bonding and consolidation of various materials in cultural relics, which has important practical application value. In this review, a systematic classification of commonly used epoxy resins, including their molecular structures, synthesis reactions and properties are provided, the problems and solutions of epoxy resin in cultural relics protection are summarized. The solutions are classified into three aspects: functional epoxy resin, blending modification, and other modification. Representative application examples of epoxy resin are listed in the field of cultural relics protection, and the development direction of epoxy resin in cultural relics protection in the future is proposed, which provides useful guidance for the modification of epoxy resin and its application in cultural relics protection in the future.

Facile preparation and property analyses of L-CNc/SiO_(2)-based composite superhydrophobic coating

In recent years,superhydrophobic coatings have received extensive attention due to their functions of waterproof,antifouling,self-cleaning,etc.However,wide applications of superhydrophobic coatings are still affected by their disadvantages of complex preparation,low mechanical properties,and poor ultraviolet(UV)resistance.In this study,cellulose nanocrystal containing a small amount of lignin(L-CNC)/SiO_(2)composite particles were usedas the main material,polydimethylsiloxane(PDMS)as the adhesive and perfluorooctyltrichlorosilane(FOTS)as the modifier to prepare superhydrophobic coatings by a one-step spray method.The resulted coating showed excellent superhydrophobicity(water contact angle(WCA)of 161°and slide angle(SA)of 7)and high abrasion resistance(capable of withstanding 50 abrasion cycles under the load of 50 g).Moreover,it still maintained good superhydrophobicity after 5 h of exposure to the UV light(1000 W),displaying its good UV resistance.This study provides theoretical and technical referencefor thesimple preparationof organic-inorganic composite superhydrophobic coatings with high abrasion resistance and good UV resistance,which is beneficial to improving the practicability and broadening the application scope of superhydrophobic coatings.