Controllable growth of gradient porous structures.
Cocontinuous phase structures of immiscible polymers can be developed under appropriate melt-blending conditions. Because of the presence of interfacial tension, such cocontinuous structures start to coarsen when heated to a temperature higher than the melting/softening temperature of both phases. In this study, a method for controllable growth of gradient porous structures utilizing variable coarsening rates in a gradient temperature field was investigated. The phase structure coarsens at a higher rate in higher temperature regions but at a slower rate in lower temperature regions, resulting in the generation of a gradient phase morphology. Subsequent dissolution of one phase in the binary blend yields a gradient porous structure made of the remaining polymer component. A polystyrene/poly(lactic acid) (PLA) blend was used as a model system. By designing proper thermal boundary conditions and introducing different thermal gradients during annealing, different types of gradient porous structures of PLA were created.
Yao
Donggang
D
School of Polymer Textile and Fiber Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA. yao@gatech.edu
Zhang
Wei
W
Zhou
Jack G
JG
D019344:Lactic Acid / Q000737:chemistry*; D010316:Particle Size; D011091:Polyesters; D011108:Polymers / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry*; D016062:Porosity; D013499:Surface Properties; D013696:Temperature
D011091:Polyesters; D011108:Polymers; D011137:Polystyrenes; D019344:Lactic Acid; C033616:poly(lactide)