# Synthesis, Characterization, and Polymerization of Ge- and Sn-Substituted [2.2]Paracyclophanes toward Poly(para-xylylene) Films and Their Mechanical Properties

## TL;DR

This paper explores the synthesis and properties of polymers containing germanium or tin, comparing them to traditional chlorinated versions.

## Contribution

The study introduces new polymers with Ge or Sn and evaluates their mechanical and thermal properties using CVD polymerization.

## Key findings

- PPXs with Ge or Sn were successfully synthesized via CVD polymerization.
- The new PPXs showed preserved ductility and distinct softness trends compared to PPX-Cl.
- Surface oxidation states changed predictably after exposure to air and oxygen plasma.

## Abstract

Polymers have had widespread applications in industry
over the
past few decades. Recently, polymers incorporating heavier group 14
elements (Ge, Sn, and Pb) have gained interest since their oxides
are promising for semiconductor applications due to their high dielectric
constants and charge mobility. Poly­(p-xylylene) (PPX),
an important class of polymer, is widely recognized for its transparency,
biocompatibility, and the conformality afforded by its polymerization
method, chemical vapor deposition (CVD). In this work, PPXs incorporating
germanium or tin are prepared via CVD polymerization and the optimal
pyrolysis temperatures of their precursors are determined. The ductility,
thermal stability, crystallinity, surface topography, and comprehensive
and surface chemical compositions are investigated. Sequential changes
in the surface oxidation state are confirmed following exposure to
air and subsequent oxygen plasma treatment. Comparison of the obtained
PPXs with the widely applied chlorinated version PPX-Cl (trade name
Parylene C) revealed preserved ductility while exhibiting distinct
trends in softness.