Fabrication of porous polylactic acid films assisted by dip‐coating and template leaching techniques

Abstract

A new simple method was developed to fabricate porous polylactic acid (PLA) films coated directly on substrates. The PLA films with a controllable thickness were realized using a dip-coating technique. The pore structure of the resulting porous PLA films was tailored by utilizing phase inversion process and template leaching techniques. The experimental results show that the resulting PLA films became thicker when using the coating solution with a higher viscosity or applying a faster withdrawal speed. The porous structures (pore size and void density) of the resulting PLA films are significantly influenced by the polymer concentration, the nonsolvents, and the addition of poly(ethylene glycol) templates. The analyses of solubility parameters was utilized to explain the porous structures of the resulting PLA films in details.

Polylactic Acid Sealed Polyelectrolyte Multilayer Microchambers for Entrapment of Salts and Small Hydrophilic Molecules Precipitates

“…This is probably caused by a barrier layer of PLA on the surface of the thin film due to solvent (chloroform) evaporation. Such findings are in agreement with the reports of others . The films produced at 3–5% PLA can fill the chambers, while the 1% PLA films were rather inhomogeneous.…”

“…Another report on this topic utilized hydrothermal reactions to in situ synthesize hydrophobic carbon dots to decrease PEM permeability, suffering however from high reaction temperatures, pressure, and 20 h reaction time . These photochemical as well as hydrothermal reactions are in line with reports of reduced permeability of hydrophobic compared to hydrophilic PEM thin films. − Polylactic acid (PLA) is a hydrophobic polymer with high water as well as water vapor barrier properties. − Further advantages of PLA is its high biodegradability and mechanical strength combined with process properties comparable to conventional polymers. ,, …”

“…Despite common applications of PLA, also in the form of coatings and barriers, the amount of freely available literature dealing with the fabrication of PLA is limited since most process conditions are either patented or company secrets. ,, For these reasons, the authors dip-coated the PEM microchambers into different PLA solution concentrations [mass percent (%) = 1%, 2%, 3%, and 5%], followed by various pull out speeds (from 0.5 to 80 mm/s). As can be observed in Figure , raising the PLA concentration causes a nonlinear increase in deposited PLA thickness.…”

“…Such findings are in agreement with the reports of others. 36 The films produced at 3−5% PLA can fill the chambers, while the 1% PLA films were rather inhomogeneous. For this reason, 2% PLA was used for encapsulation and sealing manufactured at 80 mm/s pull out speed, since this speed led to no further shear thinning of the thin films (Figure S3).…”

In vitro and in vivo evaluation of porous chitosan electret membrane for bone regeneration

“…It has been reported by many researchers that different pore size, morphology, and porosity of chitosan-based materials could be prepared by template leaching, supercriticalassisted phase inversion, immersion precipitation phase inversion, and electrospinning method. [22][23][24][25] In fact, by TIPS method, the porous structure could be controlled by freezing rate and direction, solution concentration, and formation of crystal nuclei. The pore structure was also the major factor that influenced the swelling ratio of porous electret membrane, which allowed tissue fluid molecules to enter the pores.…”