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.
School of Polymer Textile and Fiber Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA. yao@gatech.edu
Donggang
D
Yao
Wei
W
Zhang
Jack G
JG
Zhou
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)