Why do bubbles stick to the straw
Carbonated drinks are manufactured by the process of carbonation. Carbonation is the process of dissolving carbon dioxide in water or an aqueous solution. In this process, carbon dioxide is added to water or an aqueous solution  under high pressure. Solubility of carbon dioxide in the aqueous solution depends on the pressure and temperature. Under high pressure the solubility of water is greatly increased and the reason why bubbles are generated when a bottle of soft drink is opened is due to the sudden drop in pressure when the bottle is opened.

The solubility of carbon dioxide in carbonated drinks strongly depends on pressure and temperature, the solubility being higher at high pressures and low temperatures. Increase in temperature or pressure would release the dissolved carbon dioxide in the form of small bubbles. 

The sealed carbonated drink is packed at a high pressure, once the bottle is opened, there occurs a sudden drop in pressure, which releases carbon dioxide as bubbles. An increase in temperature can also contribute in the increased generation of carbon dioxide. On insertion of straw into the carbonated drink the temperature around the straw increases slightly and due to the adsorptive property of the plastic straw, the generated bubbles stick on to the surface of the straw.

[1] http://en.wikipedia.org/wiki/Soft_drink#Carbonated_drinks
[2] http://www.hindu.com/seta/2006/04/06/stories/2006040601001800.htm
[3] http://en.wikipedia.org/wiki/Carbonation
[4] http://realdoctorstu.com/2011/01/11/when-i-pour-a-fizzy-drink-why-do-bubbles-stick-to-the-straw/