Construct perfect carbon nanotube/graphene nanoplate synergistic conductive network in poly(L-lactic acid) porous materials by nonsolvent-induced rapid phase separation

The poly(L-lactic acid)/carbon nanotube/graphene nanoplate (PLLA/CNTs/GNPs) porous conductive composite materials were successfully prepared by nonsolvent-induced phase separation (NIPS). Combining the synergistic effect of nanomaterials with different geometries and the network structure constructed by polymer solution phase separation, an electrically conductive channel was successfully constructed and achieved 2.78 S/m at 5 wt% nanomaterial content. The relationship between the rate of phase separation of polymer solutions and the conductive network has been investigated and it has been found that perfect conductive channels can be constructed by rapid phase separation. According to the differential scanning calorimetry, the crystal growth can be limited by the lamellar structure of the GNP, and the distribution of carbon nanomaterials, influenced by phase separation rate, therefore can be inferred by crystallinity. Moreover, combined with the good ability of nanomaterials to induce nucleation of molecular chains and the successful shortening of crystal growth by rapid phase separation, the crystal size can be reduced to form the surface microstructure which increases the surface water contact angle to 140.2(degrees). Furthermore, the distribution of nanomaterials significantly increased the thermal degradation temperature of PLLA. This work provides a facile method to fabricate a PLLA bioplastic foam and suggests excellent electrical conductivity, hydrophobicity, and high heat resistance.