STP643: Surface Analysis of Polymer and Glass

    Sparrow, GR
    Customer applications specialist, Analytical Systems, and research specialist, Central Research Laboratories, 3M Company, St. Paul, Minn

    Mismash, HE
    Customer applications specialist, Analytical Systems, and research specialist, Central Research Laboratories, 3M Company, St. Paul, Minn

    Pages: 18    Published: Jan 1978


    Abstract

    The unique physical nature of glass results in numerous surface phenomena which have long been unexplained due to difficulties experienced by analytical chemists undertaking their study. Modern, sophisticated surface analysis instrumentation now permits analysis of surfaces from the top monolayer into the bulk material.

    Detailed studies of glass surfaces provide the information necessary to understand how common cleaning, polishing, etching, and heat treatments affect the chemistry and properties of glass. Similar information obtained from studies of the first 30Å of treated polymers contributes to the understanding and explanation of their properties such as those related to oxidation, degradation, reflectance, hardness, and especially adhesion. The primary objective achieved through detailed surface analysis of the treated polymers was the knowledge necessary to develop better adhesion to polymers.

    Problems inherent in surface analysis of glass and polymers relate to their physical nature. Their surfaces are highly subject to ion migrations which are disconcerting to the analyst. The nonconductive or electrical insulating property defeats many instrumental methods of analysis. Combined high-performance ion scattering spectrometer (ISS), utilizing a recently developed cylindrical mirror analyzer (CMA), and a secondary ion mass spectrometer (SIMS) were used in these studies. The system was also equipped with a charge neutralization system and an automatic high-speed data processing device. Common soda lime glass was subjected to treatment by chromic acid, alcoholic potassium hydroxide (KOH), hydrogen fluoride (HF) vapor, and HF bath, and studied from the top monolayer to several hundred angstroms. Zirconium polished glass and various heat-treated glasses were studied similarly. Results were compared to analysis of the surface and bulk of untreated glass. A commercial polyimide, Kapton, cleaned by acid, base, solvents, and various drying techniques was surface analyzed. Surface information was correlated with original and residual contaminants and thin film bondability.

    Results indicated that most glasses are normally surface rich in sodium from 0 to about 30Å, but chemical cleaning by chromic acid, KOH, and HF vapor removes surface sodium, leaving a surface of primarily silica only. Heat treatment caused extensive concentration changes to several thousand Å. The surface carbon, nitrogen, and oxygen concentrations of a polyimide were substantially altered by simple cleaning treatments to about 30Å. However, the surface exhibiting greatest bondability of coated aluminum showed minimum contaminations due to metal such as sodium, magnesium, aluminum, silicon, potassium, calcium, and fluorine. The combined results illustrate that the extensive surface information available through modern analytical instrumentation contributes substantially toward understanding and controlling surface phenomenon not previously explained.

    Keywords:

    quantitative analysis, materials, surfaces, polymers, glass


    Paper ID: STP25606S

    Committee/Subcommittee: E42.15

    DOI: 10.1520/STP25606S


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