Accidental lab unfortunately reveals nature’s hidden art

A simple lab error reveals a whole new world of spontaneous patterns that can reshape our understanding of how complex designs emerge in engineering materials and living systems.

UCLA researchers have found that hundreds of identical, complex helical patterns can be spontaneously etched onto semiconductor surfaces through previously unknown interactions between chemical and physical forces. The discovery, published on physical review materials on March 3, provides scientists with a new experimental system formed by research patterns, the first major advancement since the field.

The discovery happened entirely by chance, when UCLA doctoral student Yilin Wong placed the sample overnight – a thin metal film coated on the glued film, which was in contact with a drop of water. When she examined it under a microscope, the experiment that was supposed to be ruined revealed something extraordinary.

“I’m trying to develop a measurement technique that sorts biomolecules on the surface by destroying and reforming chemical bonds,” Wong explained. “It’s common to immobilize DNA molecules on solid substrates. I guess no one makes the same mistake, and I happened to look under a microscope.”

This accidental glimpse reveals a beautiful spiral pattern of etching to the germanium surface by chemical reactions, a completely unexpected result that inspired the researchers’ curiosity.

Wong and Physics professor Giovanni Zocchi systematically studied the causes of these patterns and were interested in the stuttering discovery of this stuttering discovery. They created a setup where a 10-nanometer thick layer of chromium (subsequently a 4-nanometer gold layer) was evaporated onto the germanium wafer. Significant patterns appear when exposed to a mild etching solution for 24-48 hours.

“The system basically forms an electrolytic capacitor,” Zoki said.

Their research shows something fascinating: As the chemical reaction progresses, the metal film layered from the germanium surface, creating pressure, which creates metal wrinkles. These wrinkles are affected by further catalytic reactions, ultimately engraving the delicate pattern in germanium.

The researchers found that they could generate different modes by adjusting experimental parameters (such as the thickness of the metal film), namely, elbow spiral, logarithmic spiral, lotus shape, etc.

Zoki noted: “The thickness of the metal layer, the initial state of the mechanical stress of the sample, and the composition of the etching solution all play a role in determining the type of pattern of development.”

What makes this discovery particularly important is that these patterns are not pure chemicals in their origins. They stand out from the interaction between chemical and mechanical forces – in particular, residual stress in metal films determines the shape formed. This coupling between chemical reactions and mechanical deformation is rare in laboratory settings, but is essentially common.

The researchers noted that the process has a surprising similarity to biological growth, in which enzymes catalyze growth to deform cells and tissues into specific shapes, somewhat similar to those observed in Wong’s experiments.

“In the biological world, this coupling is actually everywhere,” Zoki explained. “We just don’t think about it in laboratory experiments, because most laboratory experiments about pattern formation are performed in liquids. That’s what makes this discovery so exciting. It provides us with a non-survival laboratory system where this coupling and its incredible pattern formation capabilities can be studied.”

The patterns observed in these experiments reflect the theoretical dynamics first proposed by British mathematician Alan Turing in the 1950s, who found that chemical systems can spontaneously form patterns such as stripes or polka points.

Pattern formation in chemical reactions has been studied since 1951, when Soviet chemist Boris Belousov accidentally discovered a chemical system that can oscillate spontaneously. This discovery introduces the fields of chemical pattern formation and nonequilibrium thermodynamics.

However, despite significant theoretical advances, there has been little change in the experimental system used to study the formation of chemical patterns since it was introduced seventy years ago. The Wong-Zocchi system represents the first major experimental advancement in this field that has been passed down from generation to generation.

Potential applications go beyond pure scientific curiosity. Understanding how stress affects pattern formation can help researchers better grasp the phenomenon from crack formation in engineering materials to growth patterns in biological systems.

For now, Wong and Zocchi continue to explore the parameters that affect these patterns, hoping to reveal the fundamental rules about how complex designs emerge in simple chemical and mechanical interactions, a question that has fascinated scientists since the dawn of modern chemistry and can now be answered in a new way, thanks to Fortunate’s lab errors and Curied, which can be solved in new ways.