# Evaluation of Biocompatible and Biodegradable PES/PCL Membranes for Potential Use in Biomedical Devices: From Fouling Resistance to Environmental Safety

## TL;DR

This paper evaluates PES/PCL membranes for biomedical use, showing that degradation increases porosity and permeability without affecting retention.

## Contribution

A novel approach to create biodegradable membranes with improved transport properties through PCL degradation is proposed.

## Key findings

- Degradation of PCL in membranes increased porosity and permeability without significant retention loss.
- Over 50% of PCL was removed in simulated body fluid and 70% in NaOH, enhancing membrane functionality.
- SEM analysis confirmed structural stability and increased large pore proportion after degradation.

## Abstract

The paper presents a method for obtaining partially degradable capillary membranes from a polyethersulfone/polycaprolactone (PES/PCL) mixture. PES/PCL membranes were obtained by the phase inversion technique with dry/wet spinning and then subjected to controlled degradation in an alkaline environment (1 M NaOH) and simulated body fluid (SBF with pH 7.4) using the flow method. The aim of the work was to select and apply a degradable, non-toxic, simple polymer as a removable component of the membrane structure. The degradable component of the membranes was PCL, the gradual hydrolysis of which was aimed at increasing the porosity and improving the transport properties of the membranes during operation. The membrane properties, such as hydraulic permeability coefficient (UFC), retention coefficient, and structural morphology, were assessed using scanning electron microscopy (SEM) before and after degradation. Analysis of SEM images performed with MeMoExplorerTM software showed an increase in the proportion of large pores (above 300 µm2) and total porosity of the membranes after degradation in NaOH and SBF. Low instability factor (<0.25) for all samples, both before and after degradation, confirms the good repeatability of the membrane structure. An increase in the UFC was observed, while the retention coefficients did not change significantly in the case of membranes after the etching process. The degradation of the PCL component in the membrane was assessed using the weight method. Measurements of the membrane mass loss before and after degradation confirmed the removal of over 50 wt.% of the PCL component in SBF and 70 wt.% in NaOH from the tested membranes, which resulted in an increase in permeability due to increased membrane porosity. The results indicate the possibility of using such structures as functional, partially self-regulating membranes, potentially useful in biomedical and environmental applications.