Changing the segment divider image:
[segmentControl setDividerImage:dividerimg
            forLeftSegmentState:UIControlStateNormal
              rightSegmentState:UIControlStateNormal
                     barMetrics:UIBarMetricsDefault];Or using core graphics
UIGraphicsBeginImageContextWithOptions(CGSizeMake(1, self.segControlOut.frame.size.height), NO, 0.0);
UIImage *blank = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
[self.segControlOut setDividerImage:blank
                forLeftSegmentState:UIControlStateNormal
                  rightSegmentState:UIControlStateNormal
                         barMetrics:UIBarMetricsDefault];