 Solution

ID: past-exam-of-the-mphil-in-micro-and-nanotechnology-enterprise-course-of-the-university-of-cambridge/2018/paper-1/section-b/9/i/b/solution

 Top articles  Latest articles New article in topic

Past exam of the MPhil in micro- and nanotechnology enterprise course of the University of Cambridge / 2018 / Paper 1 / Section B / 9 / i / b / Solution by

Codex  0 2026-10-20

A useful net bookkeeping reaction for thiol adsorption is

A u_{surface} + HS (C H_{2})_{n} OH ⟶ A u_{surface} - S (C H_{2})_{n} OH + H_{ads},

(1)

with removal or reaction of the hydrogen depending on environment. Equivalently, a simplified overall balance can combine two hydrogen atoms into

H_{2}

. These balances identify sulfur anchoring; they are not a claim that one elementary adsorption step universally releases hydrogen gas.

Molecules arrive at the interface, adsorb through sulfur, and reorganize laterally as coverage grows. Interactions between the chains favor packing and order, with the hydroxyl end groups facing outward. Gold surface structure, defects and adsorption conditions affect the final film.

Figure 1.
Original schematic of hydroxyl-terminated molecules anchored to gold and the through-liquid contact angle with interfacial-tension balance
. **Details**.

 Read the full article

 New to topics? Read the docs here!