Research spotlight: Deo Musinguzi

Whole blood slides off a small sheet of flexible silicone in under a third of a second. The surface beneath does not stain, does not clog, and keeps working after being sanded twenty times. That detail appears in a June 2026 Materials Letters paper, and it belongs to a run of six studies that Deo Musinguzi, a researcher at the School of Mechanical Engineering at Jiangsu University of Technology in Changzhou, China, has co-authored on laser-engineered, liquid-repelling surfaces.

The question running through all six papers is simple to state and hard to answer: can a surface shed water, blood, or steam reliably without depending on fragile chemical coatings or fussy multi-step manufacturing? Superhydrophobic surfaces, those with a water contact angle above 150 degrees where a droplet beads up into a near-perfect sphere, have been studied for decades. Their promise extends from power plant condensers and self-cleaning windows to medical devices that resist clotting. The sticking point has always been durability. Many such surfaces repel water beautifully on a lab bench and then fail after minor abrasion. Musinguzi and his collaborators attack that problem with lasers, carving micro- and nano-scale texture directly into materials instead of merely painting a coating on top.

Contact angle is the ruler here. A high angle means a droplet beads up; a low angle means it spreads. Across the six publications, reported contact angles run from 62.6 degrees, strongly wettable, to 158.4 degrees, superhydrophobic, depending on the tool and the material.

"When the texture does the real work, the surface can tolerate wear that would strip a chemical coating," Musinguzi said, describing the group's approach.

Topography, not chemistry: the acrylic test

The cleanest proof of the texture-over-chemistry idea came in a comparison of two lasers on polymethyl methacrylate, or PMMA, the transparent acrylic used in display screens, lenses, and lab-on-a-chip devices. An ultraviolet picosecond laser with pulses of 10 trillionths of a second carved fine, sharp-edged micro-pillars. An infrared nanosecond laser with pulses of 20 billionths of a second dumped heat into the plastic, melting and re-solidifying it into a rough, porous, cauliflower-like surface. The two tools are like a cold blade versus a hot wire: both cut, but one leaves clean edges while the other deforms everything it touches.

Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy found no detectable chemical change in either treated sample. Yet the wetting behavior moved in opposite directions. UV-treated surfaces reached a water contact angle of 120.2 degrees, hydrophobic, while infrared-treated ones fell as low as 62.6 degrees, hydrophilic. The paper puts it directly: surface topography, not chemistry, is the primary factor controlling PMMA wettability here. For a microfluidic chip, that opens the option of making one channel wettable and another water-shedding without adding a single drop of chemical treatment.

The PMMA work also leans on two classical wetting models that show up across the papers. In the Wenzel state, a droplet fills every crevice, wetting the full surface area. In the Cassie-Baxter state, air pockets remain trapped under the droplet, so liquid rests only on the peaks of the texture. UV picosecond laser texturing pushed PMMA into a stable Cassie-Baxter regime; the infrared nanosecond treatment drove it into Wenzel wetting. That distinction is why the shape of the texture, and not any chemical change, decides whether a drop beads or spreads.

From beading droplets to better condensers

Durability and heat transfer meet in a paper published in Surface Technology in May 2026. The team pre-coated an H62 brass substrate with a mixture of polydimethylsiloxane, or PDMS, and copper powder, then rastered an infrared nanosecond laser over it in air. The laser does two jobs at once: it carves hierarchical micro- and nano-structure, and it locks the low-surface-energy PDMS into place. The optimal recipe, scan spacing of 200 micrometers, 20 passes, 150 millimeters per second, and a PDMS-to-copper mass ratio of 2:1, produced a surface with a static water contact angle of 158.4 degrees and a sliding angle of just 6 degrees. A droplet that round barely needs a nudge before it rolls away.

The surface took abuse and kept working:

• After 45 sandpaper abrasion cycles from 800-grit paper under a 90-gram load, the contact angle was 149 degrees; after 60 cycles, 146.6 degrees.
• After 240 grams of falling sand, the contact angle stayed at 147.7 degrees, with the sliding angle loosening to 18.5 degrees.
• After 12 hours at 300 degrees Celsius, the contact angle still sat above 151.8 degrees.
• In continuous steam, superhydrophobicity held for more than nine hours before slipping to 124.2 degrees, from which a two-hour bake at 100 degrees Celsius restored it.

The energy relevance comes from condensation. In a power-plant or refrigeration condenser, steam that condenses as a continuous liquid film acts as a thermal blanket. Dropwise condensation, droplets that bead, grow, and fall away, lets the metal breathe. With pure PDMS, the heat transfer coefficient at a subcooling of 1 kelvin was already 2.12 times that of a smooth copper plate. Adding copper powder pushed that to 5.85 times the smooth plate and 2.76 times the pure PDMS coating. The copper forms a continuous three-dimensional network inside the polymer, giving heat a phonon highway, phonons being the collective vibrations that carry thermal energy through a solid, while the laser-carved texture traps air and keeps liquid from flooding the surface. The enhancement does fade toward unity as subcooling rises, which is consistent with classical dropwise condensation theory. The full parameters are reported in the Surface Technology paper.

A coating that flips under light

Some surfaces need to shed water sometimes and spread it other times. A paper in the Journal of Coatings Technology and Research built that behavior on an aluminum alloy. The process starts with infrared nanosecond laser etching to create micro-nano roughness. An epoxy resin adhesive layer is then sprayed and cured for adhesion. Finally a suspension of hexadecyltrimethoxysilane-modified titanium dioxide nanoparticles, shortened to HDTMS-TiO2, in ethanol is sprayed on top. The starting state is superhydrophobic, with a contact angle over 150 degrees. Ultraviolet irradiation oxidizes the HDTMS alkyl chains, and the same surface becomes superhydrophilic, below 5 degrees, meaning a drop spreads into a film. The wetting property switched fifteen times with contact-angle fluctuation under five degrees.

Fifteen cycles is both a milestone and a boundary. After that, local failure appears, which the authors attribute to the irreversible degradation of the HDTMS. Switchable coatings live and die by cycle count, and this one stops at fifteen under the tested conditions. That framing is useful: instead of claiming indefinite reversibility, the paper marks exactly where the chemistry gives out, which tells a manufacturer how often the coating layer would need renewal.

Blood-repellent by template

Medical devices add a harder test: blood. Whole blood is far more complex than water, with proteins, platelets, and cells that can foul a surface within minutes. The Materials Letters paper describes a template method. A nanosecond laser carves micro-groove arrays into a copper plate. That template is immersed in an ethanol suspension of TiO2 nanoparticles and HDTMS for 24 hours, during which evaporation-driven capillary forces deposit the nanoparticles while HDTMS modifies the surface. A PDMS sheet is then cast and peeled, transferring the micro-nano hierarchy into a flexible polymer. The optimum appeared at a laser power of 27 watts with a scanning interval of 100 micrometers; at 30 watts, the structure melted and collapsed.

The cast PDMS measured a water contact angle of 154.3 degrees, a sliding angle below 10 degrees, and a surface free energy as low as 8.556 millijoules per square meter. It stayed superhydrophobic after 20 sandpaper abrasion cycles. In blood experiments, whole-blood droplets slid off a 10-degree incline in 0.31 seconds. Under a 100 mL/min blood flow, no residue remained, as described in the Materials Letters paper. The significance is mechanical: the low-surface-energy micro-nano texture is embedded into the PDMS matrix rather than applied as an external coating, which is what lets it survive abrasion.

The molecular machinery underneath

Two more papers supply the why rather than the how. In a computational study published in Computational Materials Science, the team modeled a smooth PDMS substrate with the Consistent Valence Force Field and applied a uniform electric field of 0.01 to 0.07 volts per angstrom perpendicular to the surface. The strongest fields ordered interfacial water molecules into a structured hydrogen-bond network that reduced water-PDMS interaction energy. In plain terms, the electric field rearranged the first molecular layers of water so the silicone surface itself interacted less with them. The mechanism runs through the surface dipole moment. That finding offers guidance for electric-field-responsive PDMS, the kind used in electrowetting valves where a voltage decides whether a droplet sticks or slides.

Porous copper for molecular fingerprinting

A different chemistry appears in the ChemistrySelect paper on nanoporous copper. Instead of a polymer surface, the team made bulk nanoporous copper by dealloying titanium-copper alloys. Dealloying is a corrosion process turned constructive: hydrofluoric acid selectively dissolves titanium, leaving behind a three-dimensional, interpenetrating skeleton of copper ligaments. The precursor alloy's phase makeup, single-phase TiCu versus dual-phase TiCu plus TiCu2, combined with the acid concentration governed how fast dealloying proceeded, and therefore the final pore architecture. Electrochemical Tafel analysis confirmed the dual-phase precursor dissolves faster. By tuning those kinetics, the team set pore sizes between roughly 50 and 200 nanometers.

At about 150 nanometers, the material produced its strongest surface-enhanced Raman spectroscopy signal, abbreviated SERS, using Rhodamine 6G, a dye used for testing. SERS amplifies Raman scattering, essentially the molecular fingerprint of whatever chemical sits on a surface, so trace substances can be detected. The 150-nanometer sweet spot balances electromagnetic-field enhancement against plasmonic damping from titanium left behind in the porous network. The advantage of bulk nanoporous copper over nanoparticle films is that the three-dimensional structure is macroscopically crack-free, which makes it sturdier for repeated sensing use.

Where the numbers stop

Every study has edges, and several are stated plainly in the papers. The fifteen-cycle limit on the switchable aluminum coating is one. Another: in the condensation experiments, the 5.85-fold enhancement applies at a subcooling of 1 kelvin and shrinks toward parity as subcooling climbs. The blood-repellent PDMS was tested through 20 abrasion cycles, a long way from the years a catheter or implant must endure. The molecular-dynamics results are predictions from simulation, with field strengths that are useful for understanding mechanisms but not yet compared against the same conditions in an experiment. And laser tuning is unforgiving: a modest power bump from 27 to 30 watts melted the template structure in the Materials Letters study.

"Bench-top abrasion numbers will not map directly onto five years inside a human body or a power plant, and the field has been burned by that gap before," said Lena Hoffmann, a surface-chemistry consultant not involved in the research. "What's encouraging here is that the papers name their failure modes rather than papering over them. Cycle limits and thermal recovery windows are exactly the parameters a manufacturer needs."

The work was paid for by China's National Natural Science Foundation under grants 12272153 and 11872026, the Changzhou Science and Technology Bureau under CZ20253068, King Faisal University in Saudi Arabia under KFU261828, and a Jiangsu University of Technology practice-innovation grant under XSJCX22_64. None of the reviewed papers discloses a commercial funding source with a direct stake in the surfaces.

Where this goes in the next five to ten years depends less on the science than on whether these processes slot into existing manufacturing lines. Laser texturing is already a production step in several industries, which lowers the barrier. The most likely transfers are condensers, atmospheric water harvesters, and microfluidic devices where a one-step, fluorine-free laser treatment replaces multi-stage chemical coating. If the durability numbers hold under real-world cycling, and that is the open question, the result would not be a single breakthrough product so much as a quieter shift: surfaces that manage liquids with texture they were born with, not chemistry they borrowed.

Photo by Cemrecan Yurtman on Unsplash