海藻糖改性聚乙烯醇及其防雾/防霜涂层

以聚乙烯醇和羧基化海藻糖为原料合成了聚乙烯醇-g-海藻糖(PVA-g-Tre),将接枝物与少量乙二醇二甲基丙烯酸酯混合,通过光引发聚合制备了亲水性半互穿网络防雾/防霜涂层.通过核磁共振氢谱和傅里叶变换红外光谱对PVA-g-Tre的化学结构进行了表征,利用原子力显微镜、水接触角测试仪、拉曼光谱等分析了涂层表面的粗糙度、润湿性及水与大分子之间的氢键作用,并考察了涂层的透光性和防雾及防霜性能.结果表明,含有不同海藻糖接枝率PVA-g-Tre的涂层表面粗糙度较低且透光率好,与含有PVA的涂层相比,引入海藻糖提高了PVA-g-Tre涂层的亲水性和润湿性,使其同时具有良好的防雾和防霜性能.

Melittin enhanced intracellular trehalose with synergistic membrane stabilization of macromolecular protectants for cell cryopreservation

Cryopreservation plays an essential role in biobanking and cell therapy,but the physiological toxicity of traditional cryoprotectants such as glycerol and dimethyl sulfoxide(DMSO)has raised safety issues for biomedical applications.Trehalose,a nonreducing disaccharide that accumulates in desiccation-or cold-tolerant organisms,has been considered as a biocompatible cryoprotectant.Herein,a naturally occurring membrane-active cationic peptide,melittin,was utilized to facilitate membraneimpermeable trehalose entry into cells for effective cell cryopreservation.Poly(ethylene glycol)and poly(vinyl pyrrolidone)were applied as macromolecular protectants to improve the stabilization of cell membranes.Upon the optimal protocol,the postthaw recovery of human red blood cells in freezing bags at a hematocrit of~50%could achieve 82.9%with favorable cell morphologies and physiological functions.Furthermore,the cryosurvival of L929 fibroblasts reached 84.3%compared to the conventional method using 10%(v/v)DMSO.In short,this work by using trehalose and melittin provides a biocompatible solvent-free approach for long-term cryostorage of cells.

Self-healing anti-icing coatings prepared from PDMS polyurea

With the help of double hydrogen bonds between urea groups, a self-healing anti-icing coating was prepared from polydimethylsiloxane(PDMS)-based polyurea(PDMSPU) that was synthesized from bis(3-aminopropyl)-terminated PDMS and2,4-toluene diisocyanate. Furthermore, by incorporating a lubricant of inert silicone oil and the cross-linking agent of 1,3,5-tris-(4-aminophenoxy)benzene(TAPOB), the anti-icing coatings exhibited elastic, slippery and durable properties. The wettability,ice shear strength, abrasion-resistance, mechanical and self-healing properties of the prepared anti-icing coatings were systematically investigated. Results showed that the ice shear strength of the PDMSPU anti-icing coating with 150 wt% silicone oil was 7.9±2.9 kPa, significantly lower than that of pristine PDMSPU(74.7±7.2 kPa). The additional introduction of 2 wt%TAPOB could effectively counteract the adverse effect of the lubricant so that the tensile strength(~1 MPa) of the coating could be comparable to pristine PDMSPU(855±96 kPa). The PDMSPU coating containing 150 wt% silicone oil and 2 wt% TAPOB could maintain the ice shear strength below 50 kPa against 10 icing/deicing cycles and at 12.0±3.3 kPa after 5000 abrasion cycles, and exhibit self-healing properties after treating at 60°C for 10 or 15 h. The slippery self-healing PDMSPU anti-icing coatings could be suitable for anti-icing surfaces in low temperature environments.

Antifogging and antibacterial properties of amphiphilic coatings based on zwitterionic copolymers

Tackling fogging and microbial infection problems related to the endoscope lens remain challenges due to visual disturbances and bacterial threats to human health.Herein,highly transparent antifogging and antibacterial coatings were developed in a facile way by thermal curing of zwitterionic copolymers poly(n-butyl methacrylate-co-2-aminoethyl methacrylate-co-sulfobetaine methacrylate)s with 1,3,5-triformylbenzene.Characterizations of surface chemical composition and wettability suggested that the copolymer coatings exhibited amphiphilicity with a hydrophobic surface and internal hydrophilicity.The prepared amphiphilic coating exhibited excellent antifogging properties both in vivo and in vitro.The introduction of hydrophobic n-butyl methacrylate and cationic aminoethylmethacrylate could improve the stability and antibacterial capability of the coating.The growth inhibition rates of the coatings against Staphylococcus aureus and Escherichia coli were up to 99%and the copolymer coatings with the zwitterionic groups had low hemolytic rates less than 3%.The amphiphilic copolymer coatings combined antifogging and antibacterial properties may have a promising potential for applications in biomedical devices.

Enhanced anti-icing properties of branched PDMS coatings with self-regulated surface patterns

Adverse impact of icing,on either infrastructures or facilities,is the great impulsion for seeking anti-icing coatings with high performance.In this work,durable icephobic coatings with self-regulated surface patterns were developed from branched polydimethylsiloxane(PDMS)co-crosslinked with fluorinated polyhedral oligomeric silsesquioxane(POSS)through a breath figure method.The prepared coatings with patterned microstructures on the surfaces exhibited excellent anti-icing performance ascribed to micro-crack generation between ice and coating surface under a small external force.The stable cross-linked network composed of branched PDMS and fluorinated POSS endowed the coatings with durability and abrasion resistance.Low ice shear strength was achieved at approximate 19.7±2.5 kPa on coating surface with self-regulated honeycomb pattern.After experiencing 30 icing/deicing cycles,the ice shear strength of the coating varied slightly.Additionally,owing to dedication of fluorinated POSS,the coating showed merely a little increase in ice shear strength after more than 1600 abrasion cycles,which was still in the icephobic range below 50 kPa.Hence,the prepared coatings with remarkably enhanced anti-icing performance and superior mechanical stability would be promising for the practical applications.

Effect of Polyhedral Oligomeric Silsesquioxane and Sorbitol on Properties of Isotactic Polypropylene

Isotactic polypropylene（iPP） was modified by the introduction of polyhedral oligomeric silsesquioxanes（POSS） and 1,3：2,4-bis（3,4-dimethylbenzylidene）sorbitol（DMDBS）. Chemical combination of （3-mercapto）- propyl-heptaisobutyl POSS with DMDBS（POSS-DMDBS）, and physical mixing of DMDBS with octaisobutyl POSS （iso-POSS/DMDBS） or trisilanolisobutyl POSS（tri-POSS/DMDBS） were applied respectively to modifying iPP, and the effects of POSS and DMDBS on crystallization, rheological and mechanical properties of iPP were systematically investigated. The results indicate that iso-POSS/DMDBS and tri-POSS/DMDBS were more effective than POSS-DMDBS on the improvement of the crystallization behavior of iPP due to the higher crystallization temperature, while the crystal!inity of iPP containing POSS-DMDBS was enhanced, approximately approached to that of iPP containing tri-POSS/DMDBS. The tensile strength of iPP with POSS-DMDBS was significantly increased from 34 MPa to 40 MPa, as high as that of iPP with iso-POSS/DMDBS. The different effects caused by the specific interaction between POSS and DMDBS could possibly be applied in the modification of iPP.