Spider silk conducts heat oppositely to most organic materials studied

by bchenglk44 on 2012-03-08 15:04:56

Spider silk, which is closely associated with Mr. Wang Jianmin's research, is a protein fiber spun by spiders. Using this silk, spiders create functional spider webs to trap insects. Spiders can also use their own silk to construct cocoons or safe nests for their babies. A spider can swing itself using its silk, even though it may carry several times its own weight.

Mr. Wang Lihong has been searching for an English version of organic materials with thermal conductivity as well as metals. Thermal conductivity, which refers to a material's ability to conduct heat, is excellent in materials such as diamond, copper, and aluminum; however, most organic materials do not possess this capability. Several characteristics of spider silk have made Mr. Wang Jianmin want to test its thermal conductivity. Spider silk is extremely strong. In fact, the strength of spider silk is comparable to that of high-end alloy steel. Spider silk is only 4 micrometers thick, while human hair is approximately 60 micrometers thick. Mr. Wang is the first scientist to test spider silk for its ability to conduct heat.

Mr. Wang believes that his discoveries will change how scientists perceive organic materials and thermal conductivity. "Our discovery will revolutionize traditional thinking about low thermal conductivity in biological substances," he wrote in the paper. Using experimental methods, with "time and patience," Mr. Wang Jianmin found that the thermal conductivity of male spider silk is 416 watts per meter Kelvin. Compared to this, copper conducts heat at 401 watts per meter Kelvin, and skin tissue conducts heat at 6 watts per meter Kelvin, similar to melamine tableware. "This is very surprising because spider silk is an organic substance," Mr. Wang admitted. "It is the highest thermal conductivity among organic materials. Only a few materials have higher conductivity—silver and diamond," he added. Mr. Wang Jianmin also revealed that the thermal conductivity of spider silk increases when stretched. In fact, if spider silk is stretched by 20%, its conductivity increases by 20%. Generally, stretching materials would reduce conductivity. This discovery "opens a door to another option for adjusting thermal conductivity in soft materials," Mr. Wang Jianmin stated in his article. Mr. Wang Jianmin's discoveries have multifaceted impacts on military, electronic entertainment devices, industrial, and medical fields.

To determine the thermal conductivity of spider silk, eight male spiders were placed in cages (Nephila clavipes or golden silk) in a greenhouse at Iowa State University. Mr. Wang Jianmin introduced male spiders into the cages, allowing them to feed on crickets. There are many purposes for spider silk, according to NewScientist, which recently reported that it was spun into violin strings. "Strands of spider silk were used to make violin strings with a unique, exciting sound," NewScientist's Stephen Battersby wrote.

Spider silk conducts heat unlike most organic materials, according to a press release from Iowa State University on Friday. Mr. Xiaopeng Wang, an associate professor of mechanical engineering at Iowa State University, discovered after his curiosity led him to find that spider silk was better than expected.

Mr. Wang conducted several experiments with partial support from the Army Research Office and the National Science Foundation. Mechanical engineer Xiaopeng Wang collaborated with Huang Liu. Upon discovering the unique ability of spider silk to conduct heat, Mr. Wang was delighted. "I think we tried the right material," he concluded. In his paper titled "New Secrets: Exceptionally High Thermal Conductivity of Spider Silk and Its Unusual Change Under Stretching," published recently in the journal Advanced Materials, Mr. Wang found that the thermal conductivity of much spider silk surpasses most materials, including conductors like silicon, aluminum, and pure iron. The research team also found that spider silk conducts heat 1000 times more effectively than woven silkworm silk and 800 times more than other organic tissues.