Bristle for liquid-reservoir hairbrush

A bristle of a liquid-reservoir hairbrush designed for dispersing water-based solutions and other thin and non-viscous liquids over a user's scalp during hair-brushing, comprising:

• a tube which has a proximal end and a distal end, wherein the distal end has a roller-ball nozzle, and wherein the tube has a channel bounded by a tube wall, and wherein the tube wall has an internal surface;
• a feeder placed into the channel, wherein the feeder has an external surface, and wherein the external surface of the feeder either does not contact or only partially contacts the internal surface of the tube wall;
• and wherein a spacing between the external surface of the feeder and the internal surface of the tube wall is great enough so that liquid can flow between the external surface of the feeder and the internal surface of the tube wall only by gravity, but not by capillary action, and air located outside of the roller-ball nozzle can flow through the roller-ball nozzle and then between the external surface of the feeder and the internal surface of the tube wall in the direction from the roller-ball nozzle to the proximal end of the tube.