Wide Bicontinuous Compositional Windows from Co-Networks Made with Telechelic Macromonomers

Abstract

Phase-separated and self-assembled co-network materials offer a simple route to bicontinuous morphologies, which are expected to be highly beneficial for applications such as ion, charge, and oxygen transport. Despite these potential advantages, the programmed creation of co-network structures has not been achieved, largely due to the lack of well-controlled chemistries for their preparation. Here, a thiol-ene end-linking platform enables the systematic investigation of phase-separated poly(ethylene glycol) (PEG) and polystyrene (PS) networks in terms of the molecular weight and relative volume fractions of precursor polymers. The ion conductivity and storage modulus of these materials serve as probes to demonstrate that both phases percolate over a wide range of compositions, spanning PEG volume fractions from ∼0.3-0.65. Small angle X-ray scattering (SAXS) shows that microphase separation of these co-networks yields disordered structures with d-spacings that follow d∼Mn0.5, for 4.8 kg/mol<Mn<37 kg/mol, where Mn is the molecular weight of the precursor polymers at the same ratio of PEG to PS. Over this range of molecular weights and corresponding d-spacings (22-55 nm), the ion conductivity (10(-4.7) S/cm at 60 °C), thermal properties (two glass transitions, low PEG crystallinity), and mechanical properties (storage modulus ≈90 MPa at 30 °C) remained similar. These findings demonstrate that this approach to thiol-ene co-networks is a versatile platform to create bicontinuous morphologies.

An unconstrained DFT approach to microphase formation and application to binary Gaussian mixtures

“…Far from being simply a test bed of our method, Gaussian mixtures appear then to be interesting in their own sake, as the presence of bicontinuous phases is of interest for a number of applications. 41 The above results suggest that the minimization algorithm developed here may be useful in many situations in which periodic structures are formed, especially when the translational invariance is broken spontaneously and the system is allowed the freedom to choose the periodicity. Since the underlying assumption is that the density profile is periodic, this method is of course unsuited to the study of confined systems or to situations in which one is actually interested in defective configurations.…”

“…25,26 This is a noticeable result, because bicontinuous phases have prospects for interesting applications. 41 Like one-component fluids with Q ± potentials, the Gaussian mixture considered here supports multiple occupancy of the lattice sites. However, this system manages to increase its density by both increasing the site occupation number and decreasing the lattice spacing at the same time.…”

Self‐Sealing and Puncture Resistant Breathable Membranes for Water‐Evaporation Applications

“…The plant Aristolochia macrophylla , a North American liana, has a mechanism to mechanically close defects. The self-sealing membrane consisted of a waterproof and breathable, non-porous poly(ether ester) multi-block copolymer membrane (PEE; Sympatex membrane) [ 2,22 ] onto which an amphiphilic polymer co-network (APCN) [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] was polymerized. Inspired by this phenomenon, Speck and co-workers developed an airtight pneumatic membrane (as used, e.g., in infl atable boats) that is capable to close punctures by the expansion of a polyurethane-foam.…”

“…The self-sealing membrane consisted of a waterproof and breathable, non-porous poly(ether ester) multi-block copolymer membrane (PEE; Sympatex membrane) [ 2,22 ] onto which an amphiphilic polymer co-network (APCN) [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] was polymerized. The self-sealing membrane consisted of a waterproof and breathable, non-porous poly(ether ester) multi-block copolymer membrane (PEE; Sympatex membrane) [ 2,22 ] onto which an amphiphilic polymer co-network (APCN) [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] was polymerized.…”

Designed enzymatically degradable amphiphilic conetworks by radical ring-opening polymerization

“…[6][7][8][9][10][11][12][13][14][15] One of the applications of APCNs is in the stabilization and enhancement of enzymatic activity in organic solvents. [16][17][18] Other methods used for the formation of APCNs were click chemistry, 5 thiol-ene reaction, 19 Diels-Alder reaction 20 etc. [16][17][18] Other methods used for the formation of APCNs were click chemistry, 5 thiol-ene reaction, 19 Diels-Alder reaction 20 etc.…”