青年与老年手指甲表面形貌、成分与力学性能的实验分析

Analysis of surface morphology,composition and mechanical properties of fingernails of people in two age groups

应用红外光谱仪、场发射扫描电镜、差示扫描热量仪、原位纳米力学测试系统对青年(20~25岁)与老年(70~75岁)指甲的表面结构、形貌、水含量及力学性能进行了实验分析。结果表明:与青年组成员指甲相比,老年组成员指甲的PO 2、C-O、CH 2与CONH基团的峰位向高波数移动;老年组成员指甲表面比青年组成员指甲粗糙并表现出明显的纵向纹理;尽管其总含水量与青年组成员指甲相当,但老年组成员指甲结合水的含量比青年组成员指甲的低;老年组成员指甲的硬度与约化弹性模量均高于青年组成员指甲相应对比量,因此,老年组成员指甲在划痕实验中显示出更好的耐磨性,但在较大载荷时出现明显的裂纹。

Infrared spectrometer,field-emission scanning electron microscope,differential scanning calorimeter and nanomechanical testing system were used to analyze the surface structure,morphology,water content,and indentation properties of fingernails of people in two age groups,a youth group(20-25 years old)and a senior group(70-75 years old).The results reveal that the vibration peaks of PO 2,C-O,CH 2 and CONH bonds from the senior nails are shifted to long wavenumbers;the surfaces of these nails are rougher and show more directional preference than those of the young ones;and that although the total water contents of the samples from both age group are equivalent,the bound water content in the nails of the seniors is lower than that in the nails of the young people.The hardness and elastic modulus of nails of the seniors are higher,responsible for a stronger abrasion resistance to scratching but noticeable cracks under heavy load.