Soft polymers wet UiO-66 without interfacial voids

MD shows flexible PVDF and PEG fill UiO-66 surface pockets; rigid PIM-1 and PS leave microvoids and fail as 70 wt% films.

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Which UiO-66 face was modelled?

The {101} BFDH cut, ~65 Å thick, dipole-neutral, water-capped Zr–OH/μ3-OH.

How were interfaces equilibrated?

Seven NVT/NPnT cycles (Tmax 600 K; Pmax 50 kbar for PIM-1, 1 kbar else), then 10×10 ns MD.

What voids appear at UiO-66/PIM-1?

Interconnected microvoids of 13 ± 4 Å (region A) and 13 ± 3 Å (region B).

Does PVDF leave interfacial microvoids?

No—PVDF fills surface roughness and chain ends enter UiO-66 pores.

How does z-length A rank affinity?

PVDF 6 ± 1 Å (tightest) vs PIM-1 15 ± 3 Å and PS 9 ± 2 Å.

How does λs compare to bulk density?

PVDF near bulk; PS ~50%; PIM-1 only ~20% of bulk near the MOF.

What polymer stiffness correlates with voids?

PIM-1 1.26 GPa and PS 2.25 GPa vs PVDF 0.80 GPa; PEG even softer at 0.13 GPa.

Which H-bond is stronger, PEG or PVDF?

OPEG···HOUiO-66 at 1.7 Å (integral 3.6) vs FPVDF···HO at 2.0 Å (2.3).

What happens to 70 wt% UiO-66/PS films?

They crack on drying and cannot be peeled intact.

How does PEG MMM rigidity change at 70 wt% MOF?

Young's modulus from 133 ± 13 to 284 ± 124 MPa; PVDF is almost unchanged.

Who keeps MOF internal surface area?

70 wt% UiO-66/PVDF retains it; the PEG analogue has no N2 area at 77 K.

What modulus rule of thumb do they propose?

Compatible pairs use polymers with Young's modulus below 1 GPa.