Cryogenic Process to Elaborate Poly(ethylene glycol) Scaffolds. Experimental and Simulation Studies

Abstract

Porous materials are of great importance because of their multiple applications in pharmacy, catalysis, and biomedicine among others. Ice segregation induced self-assembly (ISISA) is a cryogenic technique that uses the ice as a template that forms upon immersion of a polymer solution into liquid nitrogen to obtain highly porous materials. Some highlights of this technique are its versatility, simplicity, and control over the final structure of the produced material; besides, no organic solvents are used during the process, and the material can be used without the need of further cleaning. In this contribution, the elaboration of scaffolds using a poly(ethylene glycol) aqueous solutions by an ice-template process has been studied from experimental and theoretical viewpoints. The experimental study of the process parameters, such as immersion velocity and a prescribed freezing front on the morphology, was carried out. Simulations were performed to understand the ISISA process by calculating temperature profiles and pore size as a function of time. The most important result of this study was the effect of freezing rate on pore size. The technique was optimized such that a recipe is proposed to form materials with 1–100 μm pore sizes.