Development of PLA/PEG Thermal Regulation Nanofibers Based on Coaxial Electrospinning and Exploration of Inner Spinning Solution Concentration

To develop thermal regulation nanofibers, this work used polyethylene glycol (PEG) solution and polylactic acid (PLA) solution as the inner and outer spinning fluids and developed PLA/PEG (P_oP_i) nanofibers using coaxial electrospinning process. Through XRD, FTIR, and water contact angle analysis, it was confirmed that the PLA of P_oP_i has a certain encapsulation effect on the inner layer of PEG, but the encapsulation effect decreases with the increase of PEG spinning solution concentration. PEG20 with a PEG spinning solution concentration of 20 wt% obtained smaller average diameters, while PEG40 with a PEG spinning solution concentration of 40 wt% showed a significant decrease in fiber formability and hydrophobicity. PEG significantly improved the mechanical properties of P_oP_i, and the Young’s modulus, yield stress, breaking stress, and breaking strain of PEG30 were increased by 18.24 MPa, 2.13 MPa, 3.54 MPa, and 41.65%, respectively, compared to pure PLA. The DSC curves of P_oP_i show a melting endothermic peak attributed to PEG, and the peak temperature gradually decreases with increasing PEG concentration. The P_oP_i exhibits temperature hysteresis during both heating and cooling processes, with PEG30 experiencing delays of 7.6 °C and 6.8 °C compared to pure PLA after heating and cooling for 5 s, respectively, indicating excellent thermal regulation ability. This work investigated the effect of PEG spinning solution concentration on inner and outer layer differences and the performance of P_oP_i, providing a theoretical basis for the development of coaxial electrospinning nanofibers for thermal regulation based on low-molecular-weight PEG.