Department of Mechanical and Industrial Engineering, Montana State University, Bozeman, MT, USA.
J Mech Behav Biomed Mater. 2011 Jan;4(1):117-24. doi: 10.1016/j.jmbbm.2010.09.013. Epub 2010 Oct 1.
Assessment of neural biocompatibility requires that materials be tested with exposure in neural fluids. We have studied the mechanical performance of laser bonded microjoints between titanium foil and polyimide film (TiPI) in artificial cerebrospinal fluid (CSF). The samples were exposed in CSF for two, four and twelve weeks at 37 °C. The laser microbonds showed initial degradation up to four weeks which then stabilized afterwards and retained similar strength until twelve weeks. To understand this bond degradation mechanism better, a finite element modeling approach was adopted. From the finite element results, it was revealed that bond degradation was not due to the hygroscopic expansion of polyimide. Rather, relaxation of the process induced residual stresses may have resulted in weakening of the bond strength as observed from experimental measurements.
评估神经生物相容性要求材料在神经液中进行测试。我们研究了钛箔和聚酰亚胺薄膜（TiPI）之间激光微连接在人工脑脊液（CSF）中的机械性能。样品在 37°C 的 CSF 中暴露两、四和十二周。激光微连接在最初四星期内显示出降解，然后稳定下来，并保持相似的强度直到十二周。为了更好地理解这种键合降解机制，采用了有限元建模方法。从有限元结果中可以看出，键合的降解不是由于聚酰亚胺的吸湿膨胀引起的。相反，过程诱导残余应力的松弛可能导致键合强度的减弱，正如实验测量所观察到的那样。
