Thin polymer$-$containing films are often used to protect surfaces from contaminants. Picture long entangled

polymers adsorbed onto a flat surface like the simplified schematic below. The polymer lengths are on the

order of $50-100nm.$

i$)$ Describe three techniques you could use to examine the structure of the polymers on the surface.

ii$)$ What are the potential advantages and disadvantages of using these techniques.

iii$)$ Briefly describe how the techniques work and what information you would obtain from them.

You may use diagrams to aid your answer.

An electron in a transmission electron microscopy column is accelerated using a voltage of $111V.$ What is its

de Broglie wavelength $(nm)?$ By how much should the voltage be changed to halve its de Broglie wavelength?