Higher chain length should make your micelles bulkier if that's what you aiming for. If hydrophilic chain is bulkier then the hydrophobic part, you can expect your micelles to be round (in good shape). I believe that increasing hydrophilic chain length could also increase water penetration to the hydrophobic cores by spacing out micelles and you may see slight increase in drug release.

Thank you Yasin for your Valuable information.

Hydrophilic chain can benefit the hydrophobic interaction towards drugs and benefit the the system stability. Drug release is also important post cellular uptake. Chain length should not be too long or too short, and a blance is needed.