This work targets to develop amphiphilic self-assembled PEO-b-PAAs-b-PNIPAM and PEO-b-PAAs-b-PNIPAM@PCL nanosized block copolymers (NBCPs) of poly N-isopropyl acrylamide (PNIPAM) with polyethylene oxide (PEO), and poly amino acids (PAAs) with and without polycaprolactone (PCL) via ring-opening and condensation polymerization methods. The interesting ring necklace and petunia bell-shaped flower-like morphology play an important role in both mechanical behavior and pharmacological actions. The PEO-b-PAAs-b-PNIPAM@PCL NBCP exhibits a notable antibacterial activity against gram-negative (Escherichia coli) and gram-positive (Staphylococcus aureus) with ZOI of 20 ± 4 mm and 18 ± 3 mm, respectively, with MIC 250 μg/ml. The mechanical properties of the NBCPs are measured at room temperature. The PEO-b-PAAs-b-PNIPAM@PCL NBCP possesses a higher value in each case compared to the neat polymer with the UTS 1.4651 MPa, Y 0.0050 MPa, Tensile strength at yield (1.4048 MPa), TS at break (1.4640 MPa), % elongation at yield (23.5%), elongation % at break (124%) and proportional limit (1.0082 MPa at 8%), respectively. With the improved mechanical strength, effective antibacterial activities along with sustainable drug release rate, the designed material can be used as a potential material for different biomedical applications.