Boundary-Encoded Interfacial Persistence (BEIP v1)

Why This Exists

Semicrystalline polymers frequently exhibit anomalous behavior near surfaces and interfaces. After repeated heating, cooling, or service, boundary regions may age, soften, embrittle, or crystallize differently than the bulk.

These effects are widely reported but rarely resolved. The unresolved question is simple:

Do polymer interfaces merely respond transiently to processing, or can they encode persistent physical memory that survives ordinary thermal cycling?

BEIP v1 is a deliberately minimal, pre-registered experiment designed to answer this question decisively.

The Claim Under Test

This experiment tests whether a common plastic— isotactic polypropylene (iPP)— can retain a history-dependent physical state at its boundary with a solid surface after repeated near-melt thermal cycling.

• Localized to the interface rather than the bulk
• Persistent under repeated near-melt cycling
• Erased only by crossing a true full-melt reset

What This Is Not

• Not a mechanism proposal
• Not an application roadmap
• Not a chemistry modification
• Not a performance claim

This is a boundary test designed to either survive or fail without interpretation.

Experimental Design (Pre-Registered)

Materials

• Polymer: batch-matched isotactic polypropylene (iPP)
• Film thickness: 50–200 nm (recorded per sample)
• Substrates:
  • Silicon (native oxide)
  • Silanized silicon (hydrophobic)

Thermal Reference

Melting peak temperature (Tm,peak) is determined by DSC on first heating at 10 °C/min under inert atmosphere. All protocol temperatures are defined relative to the measured Tm,peak for the batch.

Two-Arm Test Structure

Arm A — Near-Melt Cycling (Test Condition)

• Temperature: Tm,peak − 8 °C
• Adjustment rule: if adjusted, adjust only downward (to −10 °C); never higher than −8 °C
• Hold: 2 minutes
• Cycles: 8
• Cool to room temperature after final cycle

Arm B — Full-Melt Reset (Erase Control)

• Temperature: Tm,peak + 15 °C
• Hold: 15 minutes
• Cycles: 3
• Cool to room temperature after final cycle

Readouts (Observation-Only)

Atomic Force Microscopy (Primary)

• Tapping mode
• Height and phase contrast (modulus optional)
• Identical, registered coordinates for baseline, post-Arm A, and post-Arm B

AFM data is inadmissible if coordinates cannot be reliably re-found.

Differential Scanning Calorimetry (Secondary)

• Cooling scans: Tc,peak and ΔHc
• Optional reheating: ΔHm to confirm reset quality in Arm B

Single Fastest-Kill Criterion

The hypothesis of boundary-encoded interfacial persistence is conclusively falsified if:

1. AFM shows no reproducible, interface-localized, history-dependent signature after Arm A relative to baseline and Arm B across substrates and repeats, and
2. DSC shows no systematic separation between Arm A, Arm B, and baseline in Tc,peak or ΔHc beyond normal instrument and run-to-run variation.

If both conditions are met, the line closes.

What This Accomplishes

If the Effect Survives

• Demonstrates persistent physical memory localized to interfaces
• Challenges the assumption that only chemistry or full melting matter
• Establishes boundaries as state-bearing regions

If the Effect Fails

• Closes a long-standing ambiguity in polymer aging
• Confirms near-melt cycling does not preserve boundary memory in iPP
• Prevents continued drift into artifact-driven explanations