Commercially available Ga+ focused ion beam (FIB) instruments with nanometer size probe allows for in situ materials removal (sputtering) and addition (deposition) on a wide range of material. These spatially precise processes have enabled a wide range of nanofacbrication operations (e.g. specimen preparation for analysis by scanning electron microscope, transmission electron microscope, and secondary ion mass spectrometer). While there exists an established knowledge of FIB methods for sample preparation of hard materials, but FIB methodology remain underdeveloped for soft materials such as biological and polymeric materials.
As FIB is increasingly utilized for specimen preparation of polymeric materials, it is becoming necessary to formulate an information base that will allow established FIB techniques to be generalized to this spectrum of materials. A thorough understanding of the fundamental ion-solid interactions that govern the milling process can be instrumental. Therefore, in an effort to make the existing procedures more universally applicable, the interrelationships between target material, variable processing parameters, and process efficiency of the milling phenomena are examined. The roles of beam current, distance (i.e. step size) between successive FIB beam dwell and the time it spent at each dwell point (i.e. pixel dwell time) are considered as applied to FIB nanomachining of four different thermoplastic polymers: 1. low density polyethylene (LDPE), 2. high density polyethylene (HDPE), 3. Polystyrene (PS), and 4. nylon 6 (PA6). Careful characterization of such relationships is used to explain observed phenomena and predict expected milling behaviors, thus allowing the FIB to be used more efficiently with reproducible results. Applications involving different types of polymer composite fiber are presented.
|Advisor:||Griffis, Dieter P., Balik, C. Maurice|
|Commitee:||Batchelor, A. Dale, Pourdeyhimi, Behnam, Rigsbee, J. Michael|
|School:||North Carolina State University|
|Department:||Materials Science and Engineering|
|School Location:||United States -- North Carolina|
|Source:||DAI-B 74/07(E), Dissertation Abstracts International|
|Subjects:||Analytical chemistry, Materials science, Textile Research|
|Keywords:||Beam nanomachining, Biocomponent fiber, Focused ion beam, Ion polymer interactions, Micromachining, Thermoplastic polymers|
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