用表面界面性能评价生物碳素材料血液相容性的可行性研究

以类金刚石薄膜(DLC)、含硅DLC、石墨、金刚石薄膜(DF)、低温各向同性碳(LTIC)和碳化硅为材料样本,用T型关联度法对其动态凝血时间、血小板消耗率、溶血率和表面能量参数等数据进行了灰色关联分析。结果显示:(1)动态凝血时间与亲水性的表面能量参数呈正相关,与临界表面张力呈负相关,其中与界面张力的关联度最大(0.63),其次为临界表面张力(-0.43);(2)与动态凝血时间的情形刚好相反,溶血率与亲水性的表面能量参数呈负相关,而与临界表面张力呈正相关,对溶血率影响较大的仍然是界面张力(-0.43)和临界表面张力(0.29);(3)与血小板消耗率关联最大的是临界表面张力(0.68),其次为表面张力(0.32);(4)动态凝血时间与血小板消耗率、溶血率之间有较大的负关联度。结果表明:动态凝血时间取决于其表面亲水性和有限润湿的平衡,血小板消耗的基础是材料表面良好的润湿与亲水性,而材料表面的疏水作用和充分的润湿则成为溶血的推动力量;动态凝血时间与溶血率和血小板消耗率之间具有“跷跷板效应”,因而可等效地用动态凝血时间评价生物碳素材料的血液相容性。证实:以血浆蛋白吸附为先导的血小板黏附、变形而致血栓形成,是生物碳素材料的主要凝血机制;可以临界表面张力为指标评价其血液相容性。本研究为用表面界面性能评价生物碳素材料的血液相容性提供了理论依据。

生物碳素材料表面界面性能与血液相容性关系研究

采用接触角测量仪测出了三种生物碳素材料 (石墨、金刚石膜、类金刚石膜 )的表面接触角 ,计算出了它们的表面能量参数。结果表明 ,类金刚石膜表面的界面自由能最低 ,临界表面张力最小 ,极性色散比最高 ;石墨表面的界面自由能最高 ,临界表面张力最大 ,极性色散比最低 ;金刚石膜处于二者之间。因而从表面能量参数的角度可以定性地得出结论 :类金刚石膜的血液相容性优于金刚石膜 。

Performance of branched-chain extended surfactant mixed with zwitterionic or cationic surfactant

2-Hexyl-1-decanol was used as the main material to prepare a block-polyether sulfonate extended surfactant(IC_(16)P_(6)E_(6)S).The solubility and surface active properties of IC_(16)P_(6)E_(6)S were evaluated,and then the IC_(16)P_(6)E_(6)S was mixed with a cationic surfactant hexadecyl trimethyl ammonium bromide(CTAB)and a zwitterionic betaine surfactant(HAB),respectively.The effects of mixing ratios of IC_(16)P_(6)E_(6)S∶HAB and IC_(16)P_(6)E_(6)S∶CTAB on the hydrodynamic diameter and interfacial properties were discussed.The emulsification,adsorption and laboratory core displacement experiments of the binary system were tested.The results showed that the critical micelle concentration(cmc)of IC_(16)P_(6)E_(6)S in distilled water was 0.1 mmol/L and the surface tension at cmc(γcmc)was 28.53 mN/m.IC_(16)P_(6)E_(6)S showed strong synergistic effects with HAB and CTAB,and the mixed systems could effectively reduce the interfacial tension compared with single surfactants.The mixed systems with n(IC_(16)P_(6)E_(6)S)∶n(HAB)of 1∶1 and n(IC_(16)P_(6)E_(6)S)∶n(CTAB)of 1∶3 could maintain ultra-low interfacial tension(in the order of magnitude of 10^(-3)mN/m)in the salinity range of 1%-7%NaCl and low interfacial tension(in the order of magnitude of 10^(-2)mN/m)in the salinity range of 3%-7%NaCl,respectively.With the increase of salinity,the emulsion formed by the mixed surfactant system underwent the phase transition process from WinsorⅠto WinsorⅢand then to WinsorⅡ.The emulsion of mixed IC_(16)P_(6)E_(6)S/HAB system had more middle-phase emulsion volume than that of the mixed IC_(16)P_(6)E_(6)S/CTAB system,and the former emulsion system was more stable.The mixed IC_(16)P_(6)E_(6)S/HAB system also had good solubilization effect,and the amount of oil solubilization was up to 43 mL/g.Meanwhile,it had good adsorption resistance.Compared with water flooding,the depressurization rate could reach 25.00%and the recovery could be enhanced by 11.75%,indicating that the IC_(16)P_(6)E_(6)S/HAB system was more conducive to the depressurization and injection enhancement for low-permeability reservoirs.

碳相成分对DLC薄膜血液相容性影响的能量机制

以6个不同工艺条件制备的DL C薄膜为样本,在前期碳相成分与表面能量参数测定、碳相成分和表面能量参数与血小板黏附特性关联分析的基础上,用T型关联度法,进一步对碳相成分和表面能量参数进行了灰色关联分析。结果显示:(1)在6个表面能量参数中,临界表面张力与碳相成分的整体关联最大,其次为表面张力的色散分量,其它则关联较小;(2 ) DL C碳相与临界表面张力和表面张力的色散分量有较大的负关联度(- 0 .5 7,- 0 .33) ,而与亲水性的其它表面能量参数的关联度均为小于0 .2 0的正值;(3) C- H碳相和C- O碳相与临界表面张力呈较大的正相关(0 .4 8,0 .2 5 )。据此得出分析结论:(1) DL C碳相主导DL C薄膜的血液相容性,其作用机制是对表面润湿性的强抑制和亲水性的有限增强;(2 ) C- H碳相和C- O碳相促使血小板变形的能量机制是增大DL C薄膜的临界表面张力;(3)评价DL C薄膜的血液相容性,既可用临界表面张力作指标设立标准,也可以对DL C碳相的含量要求、辅以对C- H碳相和C- O碳相的含量限定设立标准。本研究为用表面性质表征DL C薄膜的血液相容性提供了理论依据。

Preparation and characterization of different surface modified SiCp reinforced Al-matrix composites

The effects of SiCp surface modifications(Cu coating,Ni coating and Ni/Cu coating)on the microstructures and mechanical properties of Al matrix composites were investigated.Surface modification of SiC particles with Cu,Ni and Cu/Ni,respectively,was carried out by electroless plating method.SiCp/Al composites were prepared by hot pressed sintering followed by hot extrusion.The results show that the surface modification of SiC particles plays an effective role,which is relative to the type of surface coating,and the interfacial bonding become stronger in the following order:untreated SiCp<Ni(Cu)-coated SiCp<Ni/Cu-coated SiCp.The Ni/Cu-coated SiCp/Al composites exhibit the best comprehensive mechanical properties,with ultimate tensile strength(σUTS)and fracture strain(εf)of 389 MPa and 6.3%,respectively.Compared with that of untreated-SiCp/Al composites,theσUTS andεf are enhanced by 19.3%and 57.5%.

Microstructures and mechanical properties of Ni-coated SiC particles reinforced AZ61 alloy composites

In order to improve the interface bonding of SiCp/AZ61 composites prepared by powder metallurgy followed by hot extrusion, the electroless plating of Ni-P coating on SiCp was carried out. The influence of Ni coating on microstructure and mechanical properties of the composites was analyzed. The results show that SiC particles distribute more uniformly in the composites after surface Ni plating and there are fewer defects in Ni-coated composite. The Ni coating reacts with the magnesium matrix forming the Mg2Ni interfacial compound layer during the sintering process. The relative density of the composite increases from 97.9% to 98.4% compared with uncoated one and the hardness of the Ni-coated composite increases more rapidly as the volume fraction of SiCp increases. The tensile test results show that the tensile strength increases from 320 to 336 MPa when the volume friction of SiC particle is 9% and the Ni-coated composites have larger elongation, indicating that Ni coating improves the interfacial bonding strength and the performance of the composites. In addition, the fracture properties of SiCp/AZ61 composites were analyzed.

Investigation of the interfacial properties for CO_2-methanol and CO_2-ethanol mixtures

An equation of state (EOS) applicable for the interfacial properties of CO2-methanol and CO2-ethanol mixtures was established by combining the cross-association EOS and the density gradient theory (DGT). The correlated surface tensions of CO2-ethanol mixtures agreed well with the experimental data. The results illustrated the temperature and pressure dependence of the cross-association between CO2 and alcohol hydroxyls in the whole vapor-liquid surface,and the influence of the cross-association on the calculation of the surface tensions of binary mixtures.

Interface Characteristics of Wood-hybrid Composites

In order to understand the current interface characteristics of wood-hybrid composites, this paper starts off from the concept of composite interface and general theory of interface form, then the inner-surface and microstructure of wood and the interface characteristics of composites, such as wood- inorganic, wood- plastic and wood- metal made by electroless plating technique, are concluded and discussed in detail. Meanwhile, on the basis of that, some points of view about how to develop the wood-hybrid composites interface research in the future are also proposed.

Dynamic effective elastic modulus of polymer matrix composites with dense piezoelectric nano-fibers considering surface/interface effect

Based on effective field method,the dynamic effective elastic modulus of polymer matrix composites embedded with dense piezoelectric nano-fibers is obtained,and the interacting effect of piezoelectric surfaces/interfaces around the nano-fibers is considered.The multiple scattering effects of harmonic anti-plane shear waves between the piezoelectric nano-fibers with surface/interface are averaged by effective field method.To analyze the interacting results among the random nano-fibers,the problem of two typical piezoelectric nano-fibers is introduced by employing the addition theorem of Bessel functions.Through numerical calculations,the influence of the distance between the randomly distributed piezoelectric nano-fibers under different surface/interface parameters is analyzed.The effect of piezoelectric property of surface/interface on the effective shear modulus under different volume fractions is also examined.Comparison with the simplified cases is given to validate this dynamic electro-elastic model.