Shape Memory Alloy (SMA) actuators are great in soft robotics for many reasons, but a major drawback is that their response rate is largely limited by the cooling rate. For many applications, it makes sense to cool (and heat) SMA’s with water. However, when a wet SMA actuates, it constricts, and the tube it is in needs to constrict with it.
This video shows how to make a corrugated tube very quickly from a drinking straw.
Joran Booth, Ph.D. in Mech. Eng. 
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