Facile and rapid synthesis of flexible PEG porous polymers as substrates for functional materials by thiol-ene click chemistry

Flexible porous polymers with good mechanical properties are very desirable in many fields, but the tedious and complicated preparation procedures severely limit their development. Herein, we report a facile and rapid preparation of the PEG porous polymers using a mixture of ethanol, polyethylene glycol diacrylate (PEGDA), and pentaerythritol tetrakis(3-mercapto-propionate) (PETMP) as porous polymers material precursor by the radicalmediated thiol-ene click chemistry combined with phase separation. The porous polymers can be formed in less than 3.5 min under UV light at low energy density (4 W m-2), and the mechanism is investigated in detail by analyzing the kinetics of thiol-ene click chemistry and the interaction between the polymer network and the porogen. The obtained porous polymers exhibit superflexibility, excellent processability, degradability and corrosion resistance for a wide range of applications, and the basic properties of porous polymers can be tuned by changing the ratio and molecular weight of the three components in the precursor, such as density (0.55-0.71 g cm-3), porosity (36.76-51.13%), mechanical properties (0.8-4.7 kPa Young's modulus) and water absorption (tunable in a wide range of 100-500%). We believe it is a promising versatile substrate that can be applied in room temperature and water-triggered shape memory, solvent-response selective separation, thermal insulation, photothermal conversion, etc.