Malleable, Mechanically Strong, and Adaptive Elastomers Enabled by Interfacial Exchangeable Bonds

Reinforcement, recycling, and functional applications are three important issues in elastomer science and engineering. It is of great importance, but rarely achievable, to integrate these properties into elastomers. Herein, we report a simple way to prepare covalently cross-linked yet recyclable, robust, and macroscopically responsive elastomer vitrimers by engineering exchangeable bonds into rubber–carbon nanodot (CD) interphase using CD as high-functionality cross-linker. The cross-linked rubbers can rearrange the network topology through transesterification reactions in the interphase, conferring the materials the ability to be recycled, reshaped, and welded. The relatively short chains bridging adjacent CD are highly stretched and preferentially rupture to dissipate energy under external force, resulting in remarkable improvements on the mechanical properties. Moreover, the malleable and welding properties allow the samples to access reconfigurable/multiple shape memory effects

Malleable, Mechanically Strong, and Adaptive Elastomers Enabled by Interfacial Exchangeable Bonds

Reinforcement, recycling, and functional applications are three important issues in elastomer science and engineering. It is of great importance, but rarely achievable, to integrate these properties into elastomers. Herein, we report a simple way to prepare covalently cross-linked yet recyclable, robust, and macroscopically responsive elastomer vitrimers by engineering exchangeable bonds into rubber–carbon nanodot (CD) interphase using CD as high-functionality cross-linker. The cross-linked rubbers can rearrange the network topology through transesterification reactions in the interphase, conferring the materials the ability to be recycled, reshaped, and welded. The relatively short chains bridging adjacent CD are highly stretched and preferentially rupture to dissipate energy under external force, resulting in remarkable improvements on the mechanical properties. Moreover, the malleable and welding properties allow the samples to access reconfigurable/multiple shape memory effects

Malleable, Mechanically Strong, and Adaptive Elastomers Enabled by Interfacial Exchangeable Bonds

Reinforcement, recycling, and functional applications are three important issues in elastomer science and engineering. It is of great importance, but rarely achievable, to integrate these properties into elastomers. Herein, we report a simple way to prepare covalently cross-linked yet recyclable, robust, and macroscopically responsive elastomer vitrimers by engineering exchangeable bonds into rubber–carbon nanodot (CD) interphase using CD as high-functionality cross-linker. The cross-linked rubbers can rearrange the network topology through transesterification reactions in the interphase, conferring the materials the ability to be recycled, reshaped, and welded. The relatively short chains bridging adjacent CD are highly stretched and preferentially rupture to dissipate energy under external force, resulting in remarkable improvements on the mechanical properties. Moreover, the malleable and welding properties allow the samples to access reconfigurable/multiple shape memory effects

Effect of HT61 against MSSA and MRSA in a murine skin bacterial infection model.

<p>A. After tape-stripping the skin, log phase MSSA was applied onto the skin area. At different time points CFU counts of the bacteria were determined. The arrow indicates the point which the treatment was initiated. B. Treatment of HT61, Bactroban and placebo (control) against MSSA and C. Treatment of HT61, Bactroban and placebo (control) against MRSA. **, P<0.01. The data has been repeated twice.</p

Thin sectioned electron micrographs of <i>S. aurues</i> analyzed by transmission electron microscopy.

<p>The cells were fixed 10 minutes after HT61 treatment. A. normal <i>S. aureus</i> cells. B. HT61 at 10 µg/ml. C. HT61 at 20 µg/ml. D. HT61 at 40 µg/ml. The scale bar is 0.2 µm.</p

The MSC₅₀ and MIC of HT61 against clinically isolated MRSA, VISA and VRSA.

<p>The MSC₅₀ and MIC of HT61 against clinically isolated MRSA, VISA and VRSA.</p

HT61-induced cytoplasmic membrane permeabilization determined by the DiSC3(5) assay.

<p>Non-multiplying and log phase MSSA were incubated with DiSC3(5) to a final concentration of 0.4 mM until no more quenching was detected, which was followed by addition of 0.1 M KCl. Different concentrations of HT61 were incubated with non-multiplying MSSA (A) and log phase MSSA (B). The changes in fluorescence were monitored at various time points. The data was confirmed in two independent experiments.</p

Effects of HT61 against stationary phase non-multiplying <i>S. pyogenes</i>, S. <i>agalactiae</i>, <i>S. epidermidis</i> and <i>P. acnes</i>.

<p>HT61 was added to the non-multiplying cultures at 20, 10, 5 and 0 µg/ml. CFU counts were carried out after 24 hours of incubation. These results were confirmed in two independent experiments.</p

Effects of HT61 and marketed antibiotics against stationary phase non-multiplying MSSA and MRSA.

<p>HT61 and the antibiotics were added to the non-multiplying cultures at different concentrations. CFU counts were carried out after 24 hours of incubation. A. Effects of HT61, amoxicillin/clavulanic acid, azithromyicin, levofloxacin, linezolid, daptomycin and mupirocin against MSSA. B. Effects of HT61, vancomycin, daptomycin and mupirocin against MRSA. These results were confirmed in two independent experiments.</p

Growth curves of methicillin-sensitive and methicillin-resistant <i>S. aureus</i>.

<p>The bacterium was grown in nutrient broth medium with shaking for 10 days. The arrows indicate the timepoints when the cultures were used for drug sensitivity test. These results were confirmed in two independent experiments.</p