Elevation of the flow temperature of gels formed by nano fibers of Poly(l-lactic acid) by surface crystallization induced by block copolymers

Polylactide cocrystals and gels

“…In another work, Matsuda et al described three procedures to elevate the flow temperature of PLLA gel. [ 89–92 ] In the first process, they took PLLA of higher molecular weight and prepared its gel in DMF. The obtained gel was immersed in a DMF solution of PLLA with lower molecular weight and cooled to a temperature of −18°C.…”

“…[ 90 ] The block copolymers with shorter PLLA blocks were observed to elevate the flow temperature with lower concentrations. [ 89 ]…”

“…In another work, Matsuda et al described three procedures to elevate the flow temperature of PLLA gel. [89][90][91][92] In the first process, they took PLLA of higher molecular weight and prepared its gel in DMF. The obtained gel was immersed in a DMF solution of PLLA with lower molecular weight and cooled to a temperature of À18 C. PLLA chains with lower molecular weight were entered into the network structure formed by PLLA of higher molecular weight, which resulted in the formation of an additional network and subsequently increased the gel's flow temperature.…”

“…[91] As another attempt to elevate the flow temperature of the PLLA gel formed by the fibrous ε crystals, the gel was immersed in the DMF solution of PLLA-b-PS to allow the block copolymer chains to penetrate into the network of PLLA. [89,90] The FE-SEM analysis revealed that the spheres of PLLA-b-PS caught inside the nanofibrous structure of PLLA gel, reinforcing the nanofibrous structure and ultimately resulting in an increment of flow temperature (Figure 11). They proposed the promotion of the transformation of the ε-crystals to α-crystals by the addition of block copolymer of PLLA-b-PS.…”

“…Source: Reproduced with permission from Elsevier, 2014 [59] block copolymers with shorter PLLA blocks were observed to elevate the flow temperature with lower concentrations. [89] Praveena et al reported the formation of supramolecular gels using PLLA/PDLA blends in DMF by inducing the formation of the crystalline complex for the first time. [60] SC gels were mainly reported in amphiphilic block copolymers.…”