Fig. 3. (A) The micro-beam test apparatus used to measure the thermal swelling coefficients for swollen MA silks. The silk sample is mounted between a glass beam and a moveable micrometer mount in the sample chamber of the aluminium, temperature-controlled stage. The stage was fixed at one end to a lead block located to one side of the microscope, and this assembly was position so that the glass beam was centred in the field of view of the microscope. This setup ensures that the temperature-controlled stage is thermally isolated from the microscope stage, so that movement of the glass beam could be used to track the thermal expansion of the temperature-controlled stage. (B) An expanded view of the temperature-controlled stage with the silk sample chamber, which shows the process for measuring the thermal swelling coefficient of MA silk. In step 1, a silk fibre is mounted in the sample chamber between the glass rod and a moveable micrometer mount, and the initial length, SL, is measured as described in the text. In step 2, the temperature is increased, and a new initial length is measured. The silk sample is then removed and the thermal expansion of the stage was measured by tracking the movement of the unloaded beam over the same temperature range (steps 3 and 4). The movement of the glass beam was subtracted from the calculated length change of the silk with temperature to give the thermal swelling coefficient of the silk.